Lochinvar KNIGHT XL 801 User Manual

KBXII-I-O Rev D  
Installation & Operation Manual  
Models: 400 - 801  
This manual must only be used by  
a qualified heating installer / service  
ƽ WARNING  
technician. Read all instructions,  
including this manual and the Knight  
XL Service Manual, before installing.  
Perform steps in the order given.  
Failure to comply could result in  
severe personal injury, death, or  
substantial property damage.  
Save this manual for future reference.  
Installation & Operation Manual  
Please read before proceeding  
Installer – Read all instructions, including  
When servicing boiler –  
ƽ WARNING  
this manual and the Knight XL Service  
Manual, before installing. Perform steps in  
the order given.  
• To avoid electric shock, disconnect electrical supply  
before performing maintenance.  
User – This manual is for use only by  
• To avoid severe burns, allow boiler to cool before  
performing maintenance.  
a
qualified heating installer/service  
technician. Refer to the User’s Information  
Manual for your reference.  
Boiler operation –  
Have this boiler serviced/inspected by  
a qualified service technician, at least  
annually.  
• Do not block flow of combustion or ventilation air to  
the boiler.  
• Should overheating occur or gas supply fail to shut off,  
do not turn off or disconnect electrical supply to  
circulator. Instead, shut off the gas supply at a location  
external to the appliance.  
Failure to comply with the above could  
result in severe personal injury, death or  
substantial property damage.  
When calling or writing about the boiler  
– Please have the boiler model and serial  
number from the boiler rating plate.  
NOTICE  
• Do not use this boiler if any part has been under water.  
The possible damage to a flooded appliance can be  
extensive and present numerous safety hazards. Any  
appliance that has been under water must be replaced.  
Consider piping and installation when  
determining boiler location.  
Any claims for damage or shortage in  
shipment must be filed immediately  
against the transportation company by the  
consignee.  
Boiler water –  
• Thoroughly flush the system (without boiler connected)  
to remove sediment. The high-efficiency heat exchanger  
can be damaged by build-up or corrosion due to sediment.  
Factory warranty (shipped with unit) does  
not apply to units improperly installed or  
improperly operated.  
• Continual fresh make-up water will reduce boiler life.  
Mineral buildup in the heat exchanger reduces heat  
transfer, overheats the stainless steel heat exchanger,  
and causes failure. Addition of oxygen carried in by  
makeup water can cause internal corrosion in system  
components. Leaks in boiler or piping must be repaired  
at once to prevent makeup water.  
Failure to adhere to the guidelines on this  
page can result in severe personal injury,  
death, or substantial property damage.  
ƽ WARNING  
If the information in this manual is not  
followed exactly, a fire or explosion may  
result causing property damage, personal  
injury or loss of life.  
ƽ WARNING  
Do not use petroleum-based cleaning or  
ƽ CAUTION  
sealing compounds in the boiler system.  
Gaskets and seals in the system may be  
damaged. This can result in substantial  
property damage.  
This appliance MUST NOT be installed in  
any location where gasoline or flammable  
vapors are likely to be present.  
Do not use “homemade cures” or “boiler  
patent medicines”. Serious damage to the  
ƽ CAUTION  
WHAT TO DO IF YOU SMELL GAS  
boiler, personnel, and/or property may  
result.  
• Do not try to light any appliance.  
• Do not touch any electric switch; do  
not use any phone in your building.  
Freeze protection uids –  
• Immediately call your gas supplier  
from a near by phone. Follow the  
gas supplier’s instructions.  
• NEVER use automotive antifreeze. Use only inhibited  
propylene glycol solutions, which are specifically  
formulated for hydronic systems. Ethylene glycol is  
toxic and can attack gaskets and seals used in hydronic  
systems.  
• If you cannot reach your gas supplier,  
call the fire department.  
• Installation and service must be  
performed by  
a
qualified installer,  
service agency, or the gas supplier.  
3
Installation & Operation Manual  
The Knight XL - How it works...  
1. Stainless steel heat exchanger  
19. High voltage junction box  
Allows system water to flow through specially designed  
coils for maximum heat transfer, while providing protection  
against flue gas corrosion. The coils are encased in a jacket that  
contains the combustion process.  
The junction box contains the connection points for the line  
voltage power and all pumps.  
20. Boiler drain port  
Location from which the heat exchanger can be drained.  
2. Combustion chamber access cover  
Allows access to the combustion side of the heat exchanger  
coils.  
21. Low voltage connection board  
The connection board is used to connect external low voltage  
devices.  
3. Blower  
The blower pulls in air and gas through the venturi (item 5).  
Air and gas mix inside the blower and are pushed into the  
burner, where they burn inside the combustion chamber.  
22. Low voltage wiring connections (knockouts)  
Conduit connection points for the low voltage connection  
board.  
4. Gas valve  
23. Condensate drain connection  
The gas valve senses the negative pressure created by the  
blower, allowing gas to flow only if the gas valve is powered and  
combustion air is flowing.  
Connects the condensate drain line to a 1/2" PVC union.  
24. Access cover - front  
5. Venturi  
Provides access to the gas train and the heat exchanger.  
The venturi controls air and gas flow into the burner.  
25. Ignition electrode  
6. Flue gas sensor (limit rated)  
Provides direct spark for igniting the burner.  
This sensor monitors the flue gas exit temperature. The  
control module will modulate and shut down the boiler if the  
flue gas temperature gets too hot. This protects the flue pipe from  
overheating.  
26. Flame inspection window  
The quartz glass window provides a view of the burner surface  
and flame.  
7. Boiler outlet temperature sensor (housed with the  
high limit sensor)  
27. Gas shutoff valve  
This sensor monitors boiler outlet water temperature (system  
supply). If selected as the controlling sensor, the control  
module adjusts boiler firing rate so the outlet temperature is  
correct.  
Manual valve used to isolate the gas valve from the gas supply.  
28. Relief valve  
Protects the heat exchanger from an over pressure condition.  
The relief valve provided with the unit is set at 50 PSI.  
8. Boiler inlet temperature sensor  
This sensor monitors return water temperature (system  
return). If selected as the controlling sensor, the control  
module adjusts the boiler firing rate so the inlet temperature is  
correct.  
29. Flame sensor  
Used by the control module to detect the presence of burner  
flame.  
30. Line voltage wiring connections (knockouts)  
9. Temperature and pressure gauge (field installed, not  
shown)  
Conduit connection points for the high voltage junction box.  
Monitors the outlet temperature of the boiler as well as the  
system water pressure.  
31. Top panel  
Removable panel to gain access to the internal components.  
10. Electronic LCD display  
The electronic display consists of 4 buttons, a navigation dial  
and a multiple line liquid crystal display.  
32. Power switch  
Turns 120 VAC ON/OFF to the boiler.  
11. Flue pipe adapter  
33. Leveling legs  
Allows for the connection of the PVC vent pipe system to the  
boiler.  
Used to allow the heat exchanger to be leveled. This is needed  
for the proper draining of the condensate from the combustion  
chamber.  
12. Burner (not shown)  
Made with metal fiber and stainless steel construction, the  
burner uses pre-mixed air and gas and provides a wide range of  
firing rates.  
34. Air shroud (Model 501 only)  
The air shroud controls air and gas flow into the burner.  
13. Water outlet (system supply)  
35. Air pressure switch  
A 1-1/2" or 2" NPT (depending on the model) water  
connection that supplies hot water to the system.  
The air pressure switch detects blocked flue/inlet conditions.  
break the control circuit, shutting the boiler down.  
14. Water inlet (system return)  
A 1-1/2" or 2" NPT (depending on the model) water connection  
that returns water from the system to the heat exchanger.  
36. Pump relay board  
The pump relay board is used to connect the boiler, system and  
DHW pumps.  
15. Gas connection pipe  
Threaded pipe connection of 1". This pipe should be connected  
to the incoming gas supply for the purpose of delivering gas to  
the boiler.  
37. Transformer  
The transformer provides 24V power to the integrated control.  
16. SMART SYSTEM Control Module  
38. High limit sensor (housed with the outlet temperature  
The SMART SYSTEM Control responds to internal and  
external signals and controls the blower, gas valve, and pumps  
to meet the heating demand.  
sensor)  
Device that monitors the outlet water temperature. If the  
temperature exceeds its setting, the integrated control will break  
the control circuit, shutting the boiler down.  
17. Manual air vent  
Designed to remove trapped air from the heat exchanger  
coils.  
39. Over-temp switch (located underneath access cover)  
Used to detect excessive temperatures on the upper coil of the  
heat exchanger.  
18. Air intake adapter  
Allows for the connection of the PVC air intake pipe to the  
boiler.  
4
Installation & Operation Manual  
The Knight XL - How it works...  
(continued)  
Model 400  
31  
30  
10  
18  
22  
32  
15  
39  
11  
24  
6
Front View - Model 400  
Rear View - Model 400  
19  
21  
37  
27  
35  
36  
16  
4
5
25  
8
1
2
14  
3
29  
28  
26  
13  
7
38  
33  
20  
17  
23  
Left Side (inside unit) - Model 400  
Right Side (inside unit) - Model 400  
5
Installation & Operation Manual  
The Knight XL - How it works...  
Model 501  
34  
18  
15  
27  
39  
4
Rear View - Model 501  
Left Side (inside unit) - Model 501  
Models 601 - 801  
5
18  
15  
27  
39  
4
Rear View - Models 601 - 801  
Left Side (inside unit) - Models 601 - 801  
6
Installation & Operation Manual  
Ratings  
Knight XL Boiler  
I=B=R Rating  
Other Specications  
Net  
Input  
MBH  
Model Number  
Boiler  
Water  
Gross  
Output  
MBH  
I=B=R  
Ratings  
Water,  
MBH  
Vent  
Size  
Water  
Gas  
Air  
Content Connections Connections Size  
Gallons  
(Note 4)  
Max  
Note: Change “N” to  
“L” for L.P. gas models.  
(Note 3)  
Min  
80  
(Note 1)  
373  
(Note 2)  
3.4  
4.2  
4.2  
5.0  
5.7  
1-1/2"  
1-1/2"  
2"  
1"  
1"  
1"  
1"  
1"  
4"  
4"  
4"  
4"  
4"  
4"  
4"  
4"  
6"  
6"  
KBN400  
KBN501  
KBN601  
KBN701  
KBN801  
399  
324  
406  
493  
574  
654  
100  
120  
140  
160  
500  
600  
700  
800  
467  
567  
660  
752  
2"  
2"  
Maximum allowed working pressure is located on the rating plate.  
NOTICE  
Notes:  
7. Knight XL boilers comply with the requirements of CSD-1  
Section CW-400 requirements as a temperature operation  
control. The manual reset high limit provided with the  
Knight XL is listed to UL353.  
1. The ratings are based on standard test procedures prescribed  
by the United States Department of Energy.  
2. Net I=B=R ratings are based on net installed radiation of  
sufficient quantity for the requirements of the building  
and nothing need be added for normal piping and pickup.  
Ratings are based on a piping and pickup allowance of 1.15.  
3. Knight XL boilers require special gas venting. Use only  
the vent materials and methods specified in the Knight XL  
Installation and Operation Manual.  
4. Standard Knight XL boilers are equipped to operate from  
sea level to 4,500 feet only with no adjustments. The boiler  
will de-rate by 4% for each 1,000 feet above sea level up to  
4,500 feet.  
UNIT EQUIPPED FOR  
HIGH ALTITUDE  
3000 FT. TO 12,000 FT.  
5. High altitude Knight XL boilers are equipped to operate  
from 3,000 to 12,000 feet only with no field adjustments.  
The boiler will de-rate by 2% for each 1,000 feet above  
3,000 feet. High altitude models are manufactured with  
a different control module for altitude operation, but the  
operation given in this manual remains the same as the  
standard boilers. A high altitude label (as shown in FIG. A)  
is also affixed to the unit.  
6. Ratings have been confirmed by the Hydronics Institute,  
Section of AHRI.  
Figure A High Altitude Label Location  
7
Installation & Operation Manual  
1 Determine boiler location  
This appliance is certified as an indoor  
appliance. Do not install the appliance  
outdoors or locate where the appliance will  
be exposed to freezing temperatures or to  
temperatures that exceed 100°F (37.8°C).  
Installation must comply with:  
ƽ WARNING  
Local, state, provincial, and national codes, laws,  
regulations, and ordinances.  
National Fuel Gas Code, ANSI Z223.1 – latest edition.  
Standard for Controls and Safety Devices for Automatically  
Fired Boilers, ANSI/ASME CSD-1, when required.  
Failure to install the appliance indoors could  
result in severe personal injury, death, or  
substantial property damage.  
National Electrical Code.  
This appliance requires a special venting  
system. The vent connection to the appliance  
must be made with the starter CPVC/  
stainless steel pipe section provided with  
the appliance. The field provided PVC vent  
fittings must be cemented to the CPVC pipe  
section. Use only the vent materials, primer  
and cement specified in this manual to make  
the vent connections. Failure to follow this  
warning could result in fire, personal injury,  
or death.  
For Canada only: B149.1 Installation Code, CSA C22.1  
Canadian Electrical Code Part 1 and any local codes.  
ƽ WARNING  
The Knight XL gas manifold and controls  
NOTICE  
met safe lighting and other performance  
criteria when the boiler underwent tests  
specified in ANSI Z21.13 – latest edition.  
Before locating the boiler, check:  
1. Check for nearby connection to:  
• System water piping  
• Venting connections  
• Gas supply piping  
Closet and alcove installations  
A closet is any room the boiler is installed in which is less than  
171 cubic feet for KBN400 models, 193 cubic feet for KBN501  
models, 223 cubic feet for KBN601 models, 247 cubic feet for  
KBN701 models and 278 cubic feet for KBN801 models.  
• Electrical power  
2. Locate the appliance so that if water connections should  
leak, water damage will not occur. When such locations  
cannot be avoided, it is recommended that a suitable  
drain pan, adequately drained, be installed under the  
appliance. The pan must not restrict combustion air  
flow. Under no circumstances is the manufacturer to be  
held responsible for water damage in connection with  
this appliance, or any of its components.  
An alcove is any room which meets the criteria for a closet with  
the exception that it does not have a door.  
Example: Room dimensions = 5 feet long, 4 feet wide, and  
8 foot ceiling = 5 x 4 x 8 = 160 cubic feet. This would be  
considered a closet for a Knight XL Boiler.  
3. Check area around the boiler. Remove any combustible  
materials, gasoline and other flammable liquids.  
For closet and alcove installations as shown  
ƽ WARNING  
in FIG.’s 1-1 and 1-2, CPVC or stainless  
steel vent material must be used inside  
the structure. The ventilating air openings  
shown in FIG.’s 1-1 and 1-2 are required  
for this arrangement. Failure to follow this  
warning could result in fire, personal injury,  
or death.  
Failure to keep boiler area clear and free  
of combustible materials, gasoline, and  
other flammable liquids and vapors can  
result in severe personal injury, death, or  
substantial property damage.  
ƽ WARNING  
4. The Knight XL must be installed so that gas control  
system components are protected from dripping or  
spraying water or rain during operation or service.  
Provide clearances:  
Clearances from combustible materials  
1. Hot water pipes—at least 1/4" (6 mm) from combustible  
materials.  
2. Vent pipe – at least 1" (25 mm) from combustible materials.  
3. See FIG.’s 1-1 and 1-2 on page 9 for other clearance  
minimums.  
5. If a new boiler will replace an existing boiler, check for  
and correct system problems, such as:  
• System leaks causing oxygen corrosion or heat exchanger  
cracks from hard water deposits.  
• Incorrectly-sized expansion tank.  
Clearances for service access  
1. See FIG.’s 1-1 and 1-2 on page 9 for recommended  
service clearances. If you do not provide the minimum  
clearances shown, it may not be possible to service the  
boiler without removing it from the space.  
• Lack of freeze protection in boiler water causing system  
and boiler to freeze and leak.  
8
Installation & Operation Manual  
1 Determine boiler location  
(continued)  
Figure 1-1 Closet Installation - Minimum Required Clearances  
For closet installations, CPVC or  
CLOSET INSTALLATION  
1/4" (6 MM) MINIMUM CLEARANCE  
ƽ WARNING  
stainless steel vent material MUST  
BE used in a closet structure due to  
elevated temperatures. Failure to  
follow this warning could result in  
fire, personal injury, or death.  
AROUND HOT WATER PIPES  
1” (25 MM) MINIMUM CLEARANCE  
AROUND VENT PIPE  
13"  
TOP  
VENTILATING  
AIR OPENING  
*
CLOSED DOOR  
12"  
VENTILATING  
*
(305 MM)  
LEFT  
AIR OPENING  
6"  
14" (356 MM)  
REAR  
0"  
RIGHT  
RECOMMENDED SERVICE CLEARANCES:  
FRONT  
TOP  
- 30” (762 mm)  
- 24” (610 mm)  
6" (152 MM)  
FRONT  
*AREA OF EACH OPENING:  
LEFT SIDE - 24” (610 mm)  
REAR  
- 24” (610 mm)  
1 SQ. INCH PER 1000 BTU PER HOUR INPUT  
WITH A MINIMUM OF 100 SQ. INCHES.  
Figure 1-2 Alcove Installation - Minimum Required Clearances  
For alcove installations, CPVC or  
stainless steel vent material MUST  
BE used in an alcove structure due  
to elevated temperatures. Failure to  
follow this warning could result in  
fire, personal injury, or death.  
ALCOVE INSTALLATION  
ƽ WARNING  
1/4" (6 MM) MINIMUM CLEARANCE  
AROUND HOT WATER PIPES  
1” (25 MM) MINIMUM CLEARANCE  
AROUND VENT PIPE  
13" (330)  
TOP  
OPEN  
FRONT  
12"  
(305 MM)  
LEFT  
14" (356 MM)  
REAR  
RECOMMENDED SERVICE CLEARANCES:  
0"  
RIGHT  
FRONT  
TOP  
- 30” (762 mm)  
- 24” (610 mm)  
18" (457 MM)  
FRONT  
LEFT SIDE - 24” (610 mm)  
REAR  
- 24” (610 mm)  
9
Installation & Operation Manual  
1 Determine boiler location  
Provide air openings to room:  
Knight XL alone in boiler room  
Residential garage installation  
Precautions  
Take the following precautions when installing the appliance  
in a residential garage. If the appliance is located in a  
residential garage, it should be installed in compliance with  
the latest edition of the National Fuel Gas Code, ANSI Z223.1  
and/or CAN/CGA-B149 Installation Code.  
1. No air ventilation openings into the boiler room are  
needed when clearances around the Knight XL are  
at least equal to the SERVICE clearances shown in  
FIG.’s 1-1 and 1-2. For spaces that do NOT supply this  
clearance, provide two openings as shown in FIG. 1-1.  
Each opening must provide one square inch free area per  
1,000 Btu/hr of boiler input.  
• Appliances located in residential garages and in  
adjacent spaces that open to the garage and are not part  
of the living space of a dwelling shall be installed so that  
all burners and burner ignition devices are located not  
less than 18 inches (46 cm) above the floor.  
Knight XL in same space with other gas or oil-red  
appliances  
1. Follow the National Fuel Gas Code (U.S.) or CSA B149.1  
(Canada) to size/verify size of the combustion/ventilation  
air openings into the space.  
• The appliance shall be located or protected so that it is  
not subject to physical damage by a moving vehicle.  
Vent and air piping  
The Knight XL requires a special vent system, designed for  
pressurized venting.  
The space must be provided with  
ƽ WARNING  
combustion/ventilation air openings  
correctly sized for all other appliances  
located in the same space as the Knight XL.  
The boiler is to be used for either direct vent installation or  
for installation using indoor combustion air. When room  
air is considered, see the General Venting Section. Note  
prevention of combustion air contamination below when  
considering vent/air termination.  
Do not install the boiler in an attic.  
Failure to comply with the above warnings  
could result in severe personal injury,  
death, or substantial property damage.  
Vent and air must terminate near one another and may be  
vented vertically through the roof or out a side wall, unless  
otherwise specified. You may use any of the vent/air piping  
methods covered in this manual. Do not attempt to install the  
Knight XL using any other means.  
2. Size openings only on the basis of the other appliances in  
the space. No additional air opening free area is needed  
for the Knight XL because it takes its combustion air  
from outside (direct vent installation).  
Be sure to locate the boiler such that the vent and air piping  
can be routed through the building and properly terminated.  
The vent/air piping lengths, routing and termination method  
must all comply with the methods and limits given in this  
manual.  
Flooring and foundation  
Flooring  
The Knight XL is approved for installation on combustible  
flooring, but must never be installed on carpeting.  
Prevent combustion air contamination  
Do not install the boiler on carpeting even  
ƽ WARNING  
if foundation is used. Fire can result,  
Install air inlet piping for the Knight XL as described in this  
manual. Do not terminate vent/air in locations that can allow  
contamination of combustion air. Refer to Table 1A, page  
11 for products and areas which may cause contaminated  
combustion air.  
causing severe personal injury, death, or  
substantial property damage.  
If flooding is possible, elevate the boiler sufficiently to prevent  
water from reaching the boiler.  
You must pipe combustion air to the boiler  
ƽ WARNING  
air intake. Ensure that the combustion air  
will not contain any of the contaminants  
in Table 1A, page 11. Contaminated  
combustion air will damage the boiler,  
resulting in possible severe personal injury,  
death or substantial property damage. Do  
not pipe combustion air near a swimming  
pool, for example. Also, avoid areas  
subject to exhaust fumes from laundry  
facilities. These areas will always contain  
contaminants.  
10  
Installation & Operation Manual  
1 Determine boiler location  
(continued)  
Table 1A Corrosive Contaminants and Sources  
When using an existing vent system to  
install a new boiler:  
Products to avoid:  
Failure to follow all instructions can result  
in flue gas spillage and carbon monoxide  
ƽ WARNING  
Spray cans containing chloro/fluorocarbons  
Permanent wave solutions  
emissions, causing severe personal injury  
or death.  
Chlorinated waxes/cleaners  
Check the following venting components before installing:  
Chlorine-based swimming pool chemicals  
Calcium chloride used for thawing  
Sodium chloride used for water softening  
Refrigerant leaks  
• Material - For materials listed for use with this appliance,  
see Section 3 - General Venting, Table 3A. For stainless  
steel venting, an adapter of the same manufacturer  
(Table 3B) must be used at the flue collar connection.  
• Size - To ensure proper pipe size is in place, see Table 3D.  
Check to see that this size is used throughout the vent  
system.  
Paint or varnish removers  
Hydrochloric acid/muriatic acid  
Cements and glues  
• Manufacturer - For a stainless steel application, you  
must use only the listed manufacturers and their type  
product listed in Table 3A for CAT IV positive pressure  
venting with flue producing condensate.  
Antistatic fabric softeners used in clothes dryers  
Chlorine-type bleaches, detergents, and cleaning solvents  
found in household laundry rooms  
• Supports - Non-combustible supports must be in place  
allowing a minimum 1/4" rise per foot. The supports  
should adequately prevent sagging and vertical slippage,  
by distributing the vent system weight. For additional  
information, consult the vent manufacturer’s  
instructions for installation.  
Adhesives used to fasten building products and other  
similar products  
Areas likely to have contaminants  
Dry cleaning/laundry areas and establishments  
Swimming pools  
• Terminations - Carefully review Sections 3 through 5 to  
ensure requirements for the location of the vent and air  
terminations are met and orientation of these fit the  
appropriate image from the Sidewall or Vertical  
options listed in the General Venting Section. For  
stainless steel vent, only use terminations listed in Table  
3B for the manufacturer of the installed vent.  
Metal fabrication plants  
Beauty shops  
Refrigeration repair shops  
Photo processing plants  
Auto body shops  
• Seal - With prior requirements met, the system should be  
tested to the procedure listed in parts (c) through (f) of  
the Removal of an Existing Boiler Section on page 12.  
Plastic manufacturing plants  
Furniture refinishing areas and establishments  
New building construction  
Remodeling areas  
With stainless steel vent, seal and connect all pipe and  
components as specified by the vent manufacturer used; with  
PVC/CPVC vent, see the Installing Vent or Air Piping Section  
on page 17.  
Garages with workshops  
If any of these conditions are not met,  
the existing system must be updated  
ƽ WARNING  
or replaced for that concern. Failure to  
follow all instructions can result in flue gas  
spillage and carbon monoxide emissions,  
causing severe personal injury or death.  
11  
Installation & Operation Manual  
1 Determine boiler location  
When removing a boiler from existing  
common vent system:  
Do not install the Knight XL into a  
ƽ DANGER  
g. Any improper operation of the common venting  
system should be corrected so the installation conforms  
with the National Fuel Gas Code, ANSI Z223.1/NFPA  
54 and/or CAN/CSA B149.1, Natural Gas and Propane  
Installation Code. When resizing any portion of the  
common venting system, the common venting system  
should be resized to approach the minimum size as  
determined using the appropriate tables in Part 11  
of the National Fuel Gas Code, ANSI Z223.1/NFPA  
and/or CAN/CSA B149.1, Natural Gas and Propane  
Installation Code.  
common vent with any other appliance.  
This will cause flue gas spillage or appliance  
malfunction, resulting in possible severe  
personal injury, death, or substantial  
property damage.  
At the time of removal of an existing boiler, the following steps  
shall be followed with each appliance remaining connected  
to the common venting system placed in operation, while  
the other appliances remaining connected to the common  
venting system are not in operation.  
a. Seal any unused openings in the common venting system.  
b. Visually inspect the venting system for proper size and  
horizontal pitch and determine there is no blockage  
or restriction, leakage, corrosion, or other deficiencies,  
which could cause an unsafe condition.  
c. Test vent system – Insofar as is practical, close all building  
doors and windows and all doors between the space  
in which the appliances remaining connected to the  
common venting system are located and other spaces of  
the building. Turn on clothes dryers and any appliance  
not connected to the common venting system. Turn on  
any exhaust fans, such as range hoods and bathroom  
exhausts, so they will operate at maximum speed. Do not  
operate a summer exhaust fan. Close fireplace dampers.  
d. Place in operation the appliance being inspected. Follow  
the lighting instructions. Adjust thermostat so appliance  
will operate continuously.  
e. Test for spillage at the draft hood relief opening after  
5 minutes of main burner operation. Use the flame of a  
match or candle, or smoke from a cigarette, cigar, or pipe.  
f. After it has been determined that each appliance  
remaining connected to the common venting system  
properly vents when tested as outlined herein, return  
doors, windows, exhaust fans, fireplace dampers, and any  
other gas-burning appliance to their previous conditions  
of use.  
12  
Installation & Operation Manual  
2 Prepare boiler  
Remove boiler from wood pallet  
Model 400  
1. After removing the outer shipping carton from the boiler,  
remove the parts box.  
1. Remove the top and front access covers from the unit (no  
tools required for removal).  
2. Remove the three screws securing the venturi to the blower.  
Note: When separating the venturi from the blower, take  
care not to damage the O-ring inside the blower (FIG. 2-2).  
2. Remove the front door to access the lag bolts in front of  
the unit (FIG. 2-1).  
3. To remove the boiler from the pallet (after removing the  
front door):  
3. Remove the four star-drive screws securing the gas valve to  
the venturi (FIG. 2-2).  
a. Remove the two lag bolts from the wood pallet  
inside the boiler (FIG. 2-1).  
b. Detach the boiler from the lag bolts in the rear of the  
unit, see FIG. 2-1.  
4. Locate the propane orifice disk from the conversion kit bag.  
Verify that the stamping on the orifice disk matches the  
boiler size (Model 400 - 8.0 LP orifice stamping).  
5. Remove the existing orifice from the O-ring in the side of the  
gas valve and replace it with the orifice from the kit. Position  
and secure the orifice in the valve as shown in FIG. 2-2.  
Do not drop the boiler or bump the jacket  
NOTICE  
on the floor or pallet. Damage to the boiler  
can result.  
6. Reposition the gas valve against the venturi and replace the  
star-drive screws (FIG. 2-2) securing the valve to the venturi.  
Figure 2-1 Boiler Mounted on Shipping Pallet  
7. Inspect the O-ring inside the blower. Handle the O-ring  
with care, do not damage. Reposition the venturi against the  
blower and replace the screws securing the venturi to the  
blower (FIG. 2-2).  
8. After installation is complete, attach the propane conversion  
label (in the conversion kit bag) next to the boiler rating  
plate. Attach the LP caution label (in the conversion kit bag)  
to the left side of the unit in the lower left corner.  
. 2  
9. Replace the top and front access covers.  
After converting to LP, check combustion  
ƽ WARNING  
Gas conversions  
per the Start-up procedure in Section 10  
of this manual. Failure to check and verify  
combustion could result in severe personal  
injury, death, or substantial property damage.  
For a boiler already installed, you must  
ƽ WARNING  
turn off gas supply, turn off power and  
allow boiler to cool before proceeding.  
You must also completely test the boiler  
after conversion to verify performance  
as described under Start-up, Section 10  
of this manual. Failure to comply could  
result in severe personal injury, death, or  
substantial property damage.  
Model 400: Inspect the O-ring when the  
blower is disassembled. The O-ring must  
be in good condition and must be installed.  
Failure to comply will cause a gas leak,  
resulting in severe personal injury or death.  
ƽ DANGER  
For the 400 Model you must install a  
propane orifice to operate the Knight XL  
on propane gas. Verify when installing that  
the orifice size marking matches boiler size  
(Model 400 - 8.0 LP orifice stamping).  
Figure 2-2 Installing Propane Orice - Model 400  
BLOWER  
O-RING  
VENTURI  
SCREWS  
Models 501 - 801 do not require an orifice  
installation for propane operation, but  
they will require a valve adjustment.  
QTY. 3  
SCREWS  
QTY. 4  
O-RING  
BRASS ORIFICE  
GAS VALVE  
13  
Installation & Operation Manual  
2 Prepare boiler  
Model 501  
After converting to LP, check combustion  
per the Start-up procedure in Section  
10 of this manual. Failure to check and  
verify combustion could result in severe  
personal injury, death, or substantial  
property damage.  
ƽ WARNING  
1. Remove the top access cover from the unit (no tools  
required for removal).  
2. Turn the adjustment screw on the gas valve clockwise until  
it stops. Then turn the adjustment screw counterclockwise  
four and three quarter (4 3/4) turns (see FIG. 2-3).  
Figure 2-4 Gas Valve Adjustment - Models 601 - 801  
3. Use a combustion analyzer to verify CO2 is within the range  
of 9.6 – 10.5%. If not, adjust the screw counterclockwise  
incrementally to raise CO2 and clockwise to lower CO2  
(FIG. 2-3).  
COVER  
ALLEN WRENCH  
4. After adjustment is complete, attach the propane conversion  
label (in the conversion kit bag) next to the boiler rating  
plate. Attach the LP caution label (in the conversion kit bag)  
to the left side of the unit in the lower left corner.  
ADJUSTMENT SCREW  
5. Replace the top access cover.  
After converting to LP, check combustion  
ƽ WARNING  
per the Start-up procedure in Section 10  
of this manual. Failure to check and verify  
combustion could result in severe personal  
injury, death, or substantial property  
damage.  
Figure 2-3 Gas Valve Adjustment - Model 501  
ALLEN WRENCH  
Leveling the boiler  
1. Set the boiler in place and check level.  
a) Adjust legs if necessary to level boiler, see FIG. 2-5  
below.  
Figure 2-5 Leveling Legs on the Boiler  
ADJUSTMENT SCREW  
SCREWDRIVER  
SLOT  
Models 601 - 801  
1. Remove the top access cover from the unit (no tools  
required for removal).  
2. Remove the cover on top of the gas valve (FIG. 2-4).  
3. Turn the adjustment screw on top of the gas valve clockwise  
one and three quarter (1 3/4) turns on the 601 Model, one  
and a half (1 1/2) turns on the 701 Model, and one turn on  
the 801 Model (see FIG. 2-4).  
LOWER  
RAISE  
4. Use a combustion analyzer to verify CO2 is within the range  
of 9.6 – 10.5%. If not, adjust the screw counterclockwise  
incrementally to raise CO2 and clockwise to lower CO2  
(FIG. 2-4).  
5. After adjustment is complete, attach the propane conversion  
label (in the conversion kit bag) next to the boiler rating  
plate. Attach the LP caution label (in the conversion kit  
bag) to the left side of the unit in the lower left corner.  
6. Replace the gas valve cover along with the top access cover.  
14  
Installation & Operation Manual  
3 General venting  
Direct venting options - Sidewall Vent  
Stainless Steel  
Two Pipe  
See Figure 4-1C  
PVC/CPVC Two Pipe  
See Figure 4-1A  
PVC/CPVC Alternate  
Two Pipe  
See Figure 4-2A  
PVC/CPVC Concentric  
See Figure 4-7  
Models 400 - 601 Only  
Stainless Steel  
Alternate Two Pipe  
See Figure 4-2B  
15  
Installation & Operation Manual  
3 General venting  
Direct venting options - Vertical Vent  
PVC/CPVC  
Two Pipe  
PVC/CPVC  
Concentric  
See Figure 5-5  
Models 400 - 601 Only  
Stainless Steel  
Two Pipe  
See Figure 5-1A  
See Figure 5-1B  
Direct venting options - Vertical Vent, Sidewall Air  
PVC/CPVC  
Stainless Steel  
Vertical Vent, Sidewall Air  
Vertical Vent, Sidewall Air  
Stainless steel vent/air design and terminations will vary slightly by manufacturer.  
NOTICE  
16  
Installation & Operation Manual  
3 General venting  
(continued)  
Install vent and combustion air piping  
The Knight XL must be vented and  
supplied with combustion and ventilation  
Insulation should not be used on PVC  
or CPVC venting materials. The use of  
insulation will cause increased vent wall  
temperatures, which could result in vent  
pipe failure.  
ƽ DANGER  
ƽ WARNING  
air as described in this section. Ensure the  
vent and air piping and the combustion  
air supply comply with these instructions  
regarding vent system, air system, and  
combustion air quality. See also Section 1  
of this manual.  
Requirements for installation in  
Canada  
Inspect finished vent and air piping  
thoroughly to ensure all are airtight and  
comply with the instructions provided and  
with all requirements of applicable codes.  
1. Installations must be made with a vent pipe system  
certified to ULC-S636.  
IPEX is an approved vent manufacturer in Canada  
supplying vent material listed to ULC-S636.  
Failure to provide a properly installed vent  
and air system will cause severe personal  
injury or death.  
2. The first three (3) feet of plastic vent pipe from the  
appliance flue outlet must be readily accessible for visual  
inspection.  
PVC/CPVC vent piping materials  
Use only the materials listed in Table 3A  
ƽ WARNING  
3. The components of the certified vent system must not be  
interchanged with other vent systems or unlisted  
pipe/fittings. For concentric vent installations, the inner  
vent tube must be replaced with field supplied certifiedvent  
material to comply with this requirement.  
(pg. 18) for vent pipe, and fittings. Failure  
to comply could result in severe personal  
injury, death, or substantial property  
damage.  
Installation must comply with local  
NOTICE  
Improper installation of PVC or CPVC  
ƽ CAUTION  
requirements and with the National Fuel  
systems may result in injury or death.  
Gas Code, ANSI Z223.1 for U.S. installations  
or CSA B149.1 for Canadian installations.  
Installing vent or air piping  
For closet and alcove installations, CPVC  
ƽ WARNING  
Use only cleaners, primers, and solvents that  
NOTICE  
or stainless steel material MUST BE used in  
are approved for the materials which are  
a closet/alcove structure. Failure to follow  
this warning could result in fire, personal  
injury, or death.  
joined together.  
1. Work from the boiler to vent or air termination. Do not  
exceed the lengths given in this manual for the air or vent  
piping.  
All PVC vent pipes must be glued, properly  
NOTICE  
supported, and the exhaust must be pitched  
a minimum of a 1/4 inch per foot back to  
the boiler (to allow drainage of condensate).  
2. Cut pipe to the required lengths and deburr the inside and  
outside of the pipe ends.  
This appliance requires a special venting  
system.Theventconnectiontotheappliance  
3. Chamfer outside of each pipe end to ensure even cement  
distribution when joining.  
ƽ WARNING  
must be made with the starter CPVC pipe  
section provided with the appliance if PVC/  
CPVC vent is to be used. For stainless steel  
venting use an adapter from Table 3B (page  
20) that corresponds with the intended  
vent manufacturer to be used and discard  
the CPVC starter piece. The field provided  
vent fittings must be cemented to the CPVC  
pipe section using an “All Purpose Cement”  
suitable for PVC and CPVC pipe. Use only  
the vent materials, primer, and cement  
specified in this manual to make the vent  
connections. Failure to follow this warning  
could result in fire, personal injury, or  
death.  
4. Clean all pipe ends and fittings using a clean dry rag.  
(Moisture will retard curing and dirt or grease will prevent  
adhesion.)  
5. Dry fit vent or air piping to ensure proper fit up before  
assembling any joint. The pipe should go a third to  
two-thirds into the fitting to ensure proper sealing after  
cement is applied.  
17  
Installation & Operation Manual  
3 General venting  
6. Priming and Cementing:  
f. While primer is still wet, apply an even coat of  
approved cement to the fitting socket.  
a. Handle fittings and pipes carefully to prevent  
contamination of surfaces.  
g. Apply a second coat of cement to the pipe.  
h. While the cement is still wet, insert the pipe into the  
fitting, if possible twist the pipe a 1/4 turn as you insert  
it. NOTE: If voids are present, sufficient cement was  
not applied and joint could be defective.  
b. Apply a liberal even coat of primer to the fitting  
socket.  
c. Apply a liberal even coat of primer to the pipe end to  
approximately 1/2" beyond the socket depth.  
d. Apply a second primer coat to the fitting socket.  
e. While primer is still wet, apply an even coat of  
approved cement to the pipe equal to the depth of  
the fitting socket.  
j. Wipe excess cement from the joint removing ring or  
beads as it will needlessly soften the pipe.  
Table 3A Vent Pipe, and Fittings  
All vent pipe materials and ttings must comply with the following:  
Standards for installation in:  
Item  
Material  
United States  
Canada  
PVC Plastic Pipe, Schedules 40, 80, & 120  
PVC Plastic Pipe Fittings, Schedule 40  
PVC Plastic Pipe Fittings, Schedule 80  
ANSI/ASTM D1785  
ANSI/ASTM D2466  
ANSI/ASTM D2467  
CPVC and PVC venting must be ULC-S636  
Certied. IPEX is an approved manufacturer  
in Canada supplying vent material listed to  
ULC-S636.  
Vent pipe and  
ttings  
PVC - DWV Pipe and Fittings  
CPVC Plastic Pipe, Schedule 40 & 80  
CPVC Plastic Pipe Fittings, Schedule 80  
AL29-4C  
ANSI/ASTM D2665  
ANSI/ASTM F441  
ANSI/ASTM F439  
UL1738  
ULC-S636  
NOTICE: DO NOT USE CELLULAR (FOAM) CORE PIPE  
Approved Stainless Steel Vent Manufacturers  
Make  
Model  
FasNSeal Vent / FasNSeal Flex* Vent  
Z-Vent  
ProTech Systems (Simpson Dura-Vent Co.)  
Z-Flex (Nova Flex Group)  
Heat Fab (Selkirk Corporation)  
Saf-T Vent  
*Use of FasNSeal Flex smooth inner wall vent is to be used in vertical or near vertical sections only, taking precaution to ensure  
no sagging occurs of the vent system. Connect to the FasNSeal rigid vent using specially designed adapters and sealing method,  
see manufacturer’s instructions.  
PVC/CPVC air intake/vent connections  
1. Combustion Air Intake Connector (FIG.’s 3-9 and 3-10) - Used to provide combustion air directly to the unit from  
outdoors. A fitting is provided on the unit for final connection. Combustion air piping must be supported per guidelines  
listed in the National Mechanical Code, Section 305, Table 305.4 or as local codes dictate.  
2. Vent Connector (FIG.’s 3-9 and 3-10) - Used to provide a passageway for conveying combustion gases to the outside.  
Transition fittings are provided with the unit for final connection. Vent piping must be supported per the National Building  
Code, Section 305, Table 305.4 or as local codes dictate.  
Figure 3-9 Near Boiler PVC/CPVC Venting - Models 400 - 601 Figure 3-10 Near Boiler PVC/CPVC Venting -  
Models  
701 - 801  
AIR  
VENT  
AIR  
VENT  
6” COUPLING  
(FIELD SUPPLIED)  
*
6” CPVC  
STARTER  
* 4” CPVC STREET ELBOW  
PIECE  
MAY BE SUBSTITUTED  
(FACTORY SUPPLIED)  
4" CPVC PIPE SUPPLIED WITH  
BOILER MUST BE USED FOR VENT CONNECTION  
NOTE: CPVC VENT OR STAINLESS STEEL PIPE AND  
VENT FITTINGS MUST BE USED IN CLOSET AND  
ALCOVE INSTALLATIONS.  
THE 6” STAINLESS STEEL ADAPTER SUPPLIED  
WITH THE BOILER MUST BE USED FOR VENT  
CONNECTION TO PVC/CPVC. THE 6” CPVC  
STARTER PIECE MUST BE USED FOR PVC ONLY.  
18  
Installation & Operation Manual  
3 General venting  
(continued)  
When a sidewall or vertical rooftop combustion air supply  
system is disconnected for any reason, the air inlet pipe must  
be resealed to ensure that combustion air will be free of  
contaminants and supplied in proper volume.  
Air inlet pipe materials:  
The air inlet pipe(s) must be sealed. Choose acceptable  
combustion air inlet pipe materials from the following list:  
PVC, CPVC or ABS  
Dryer Vent or Sealed Flexible Duct (not recommended for  
rooftop air inlet)  
Galvanized steel vent pipe with joints and seams sealed as  
specified in this section.  
Type “B” double-wall vent with joints and seams sealed as  
specified in this section.  
Failure to properly seal all joints and seams  
ƽ DANGER  
as required in the air inlet piping may  
result in flue gas recirculation, spillage  
of flue products and carbon monoxide  
emissions causing severe personal injury  
or death.  
Stainless steel vent  
AL29-4C, stainless steel material to be sealed to  
specification of its manufacturer.  
This product has been approved for use with stainless steel  
using the manufacturers listed in Table 3A.  
*Plastic pipe may require an adapter (not provided) to  
transition between the air inlet connection on the appliance  
and the plastic air inlet pipe.  
Use only the materials, vent systems,  
ƽ WARNING  
and terminations listed in Table 3B.  
DO NOT mix vent systems of different  
types or manufacturers, unless listed in  
this manual. Failure to comply could  
result in severe personal injury, death, or  
substantial property damage.  
Using vent or air intake materials other  
ƽ WARNING  
than those specified, failure to properly  
seal all seams and joints or failure to follow  
vent pipe manufacturer’s instructions can  
result in personal injury, death or property  
damage. Mixing of venting materials will  
void the warranty and certification of the  
appliance.  
Installations must comply with applicable  
NOTICE  
national, state, and local codes. Stainless  
steel vent systems must be listed as a  
UL-1738 approved system for the United  
States and a ULC-S636 approved system  
for Canada.  
The use of double-wall vent or insulated  
NOTICE  
material for the combustion air inlet pipe is  
recommended in cold climates to prevent  
the condensation of airborne moisture in  
the incoming combustion air.  
Installation of a stainless steel vent system  
NOTICE  
should adhere to the stainless steel vent  
Sealing of Type “B” double-wall vent material or galvanized  
vent pipe material used for air inlet piping on a sidewall or  
vertical rooftop Combustion Air Supply System:  
manufacturer’s installation instructions  
supplied with the vent system.  
The installer must use a specific vent starter  
NOTICE  
a. Seal all joints and seams of the air inlet pipe using either  
Aluminum Foil Duct Tape meeting UL Standard 723 or  
181A-P or a high quality UL Listed silicone sealant such as  
those manufactured by Dow Corning or General Electric.  
adapter at the flue collar connection,  
supplied by the vent manufacturer to  
adapt to its vent system. See Table 3B for  
approved vent adapters. Discard CPVC  
starter piece.  
b. Do not install seams of vent pipe on the bottom of  
horizontal runs.  
c. Secure all joints with a minimum of three sheet metal  
screws or pop rivets. Apply Aluminum Foil Duct Tape or  
silicone sealant to all screws or rivets installed in the vent  
pipe.  
d. Ensure that the air inlet pipes are properly supported.  
The PVC, CPVC, or ABS air inlet pipe should be cleaned and  
sealed with the pipe manufacturer’s recommended solvents  
and standard commercial pipe cement for the material used.  
The PVC, CPVC, ABS, Dryer Vent or Flex Duct air inlet pipe  
should use a silicone sealant to ensure a proper seal at the  
appliance connection and the air inlet cap connection. Dryer  
vent or flex duct should use a screw type clamp to seal the vent  
to the appliance air inlet and the air inlet cap. Proper sealing  
of the air inlet pipe ensures that combustion air will be free of  
contaminants and supplied in proper volume.  
19  
Installation & Operation Manual  
3 General venting  
Table 3B Approved Stainless Steel Terminations and Adapters  
ProTech  
Heat Fab  
Z Flex  
FasNSeal  
Saf-T Vent  
Z-Vent  
Model  
Intake  
Air  
Intake  
Air  
Termination  
Boiler  
Flue  
Boiler Intermediate  
Adapter Adapter  
Flue  
Termination  
Boiler  
Flue  
Intake Air  
Adapter Termination  
Adapter Termination Termination  
Termination  
FSBS4  
F303759  
FSAIH04  
303888  
9492  
5400CI  
2SVSTP04  
2SVSRCX04  
KB285600 9454BUREZ-1*  
9414TERM 2SVSLA04  
2SVSTEX0490  
400-601  
701-801  
FSRC4(R.C)  
F303759  
FSAIH04  
303888  
(Intake  
Only)  
FSBS6  
* = This adapter must be used in addition to the boiler adapter for Saf-T vent pipe as shown in FIG. 3-11, unless approved vent  
other than standard diameter is used. Consult a Heat Fab representative for questions.  
Figure 3-11 Near Boiler Stainless Steel Venting Models  
Table 3C Stainless Steel Vent Termination Kit(s)  
400 - 601  
Model  
Kit Number  
701 - 801  
KIT3137  
VENT  
Stainless  
connections  
steel  
air  
intake/vent  
1. Combustion Air Intake Connector (FIG.’s 3-11 and  
3-12) - Used to provide combustion air directly to the  
unit from outdoors. A fitting is provided on the unit  
for final connection. Combustion air piping must be  
supported per guidelines listed in the National  
Mechanical Code, Section 305, Table 305.4 or as local  
codes dictate.  
2. Vent Connector (FIG.’s 3-11 and 3-12) - Used to  
4" S.S. ADAPTER  
4" S.S. INTERMEDIATE  
(FOR SAF-T VENT ONLY)  
provide  
a
passageway for conveying combustion  
gases to the outside. A transition fitting is provided  
on the unit for final connection. Vent piping must  
be supported per the National Building Code, Figure 3-12 Near Boiler Stainless Steel Venting Models  
Section 305, Table 305.4 or as local codes dictate.  
701 - 801  
20  
Installation & Operation Manual  
3 General venting  
(continued)  
The Knight XL uses model specific combustion air intake and  
vent piping sizes as detailed in Table 3D below.  
Vent and air piping  
Vent and air system:  
Table 3D Air Intake/Vent Piping Sizes  
Installation must comply with local  
NOTICE  
requirements and with the National Fuel Gas  
Code, ANSI Z223.1 for U.S. installations or  
CSA B149.1 for Canadian installations.  
Model  
400 - 601  
701 - 801  
Air Intake  
Vent  
4 inches (102 mm)  
4 inches (102 mm)  
4 inches (102 mm)  
6 inches (152 mm)  
You must also install air piping from outside to the boiler air  
intake adapter. The resultant installation is direct vent (sealed  
combustion).  
Increasing or decreasing combustion air  
or vent piping is not authorized.  
NOTICE  
You may use any of the vent/air piping methods covered in this  
manual. Do not attempt to install the Knight XL using any  
other means.  
Minimum  
/
Maximum  
allowable  
combustion air and vent piping lengths  
are as follows:  
DO NOT mix components from different  
ƽ WARNING  
systems. The vent system could fail,  
Combustion Air = 12 equivalent feet (3.7 m) minimum /  
100 equivalent feet (30.5 m) maximum  
causing leakage of flue products into the  
living space. Use only approved stainless  
steel, PVC or CPVC pipe and fittings. For  
PVC/CPVC use with primer and cement  
specifically designed for the material used.  
Vent = 12 equivalent feet (3.7 m) minimum / 100 equivalent  
feet (30.5 m) maximum  
When determining equivalent combustion air and vent  
length, add 5 feet (1.5m) for each 90° elbow and 3 feet (.9 m)  
for each 45° elbow.  
Vent, air piping and termination:  
The Knight XL vent and air piping can be installed through the  
roof or through a sidewall. Follow the procedures in this manual  
for the method chosen. Refer to the information in this manual  
to determine acceptable vent and air piping length.  
EXAMPLE: 20 feet (6 m) of PVC pipe + (3) 90° elbows +  
(3) 45° elbows + (1) concentric vent kit (CVK3007) = 49  
equivalent feet (15 m) of piping.  
Optional room air  
The appliance output rating will reduce  
NOTICE  
by up to 1.5% for each 25 feet (68 m) of  
Optional room air is intended for  
NOTICE  
vent length.  
commercial applications. Combustion air  
piping to the outside is recommended for  
residential applications.  
Table 3E Concentric Vent Kit Equivalent Vent Lengths  
Commercial applications utilizing the Knight XL boiler may  
be installed with a single pipe carrying the flue products to the  
outside while using combustion air from the equipment room.  
In order to use the room air venting option the following  
conditions and considerations must be followed.  
Equivalent  
Model  
Kit Number  
Vent Length  
5 Feet (1.5 m)  
30 Feet (9 m)  
30 Feet (9 m)  
400  
501  
601  
CVK3007  
CVK3007  
CVK3007  
The unit MUST be installed with the appropriate  
room air kit (Table 3F).  
Removing from existing vent  
The equipment room MUST be provided with  
properly sized openings to assure adequate  
combustion air. Please refer to instructions provided  
with the room air kit.  
Follow the instructions in Section 1, page 12 of this manual  
when removing a boiler from an existing vent system.  
There will be a noticeable increase in the noise level  
during normal operation from the inlet air opening.  
Using the room air kit makes the unit vulnerable to  
combustion air contamination from within the  
building. Please review Section 1, Prevent  
Combustion Air Contamination, to ensure proper  
installation.  
Vent system and terminations must comply with the  
standard venting instructions set forth in this manual.  
21  
Installation & Operation Manual  
3 General venting  
If the boiler combustion air inlet  
When utilizing the single pipe method,  
ƽ WARNING  
ƽ WARNING  
is located in a laundry room or  
pool facility, for example, these  
areas will always contain hazardous  
contaminants.  
provisions for combustion and ventilation  
air must be in accordance with Air for  
Combustion and Ventilation, of the  
latest edition of the National Fuel Gas  
Code, ANSI Z223.1, in Canada, the latest  
edition of CGA Standard B149 Installation  
Code for Gas Burning Appliances and  
Equipment, or applicable provisions of the  
local building codes.  
To prevent the potential of severe  
personal injury or death, check for  
areas and products listed in Table 1A,  
page 11 before installing the boiler or  
air inlet piping.  
ƽ WARNING  
Table 3F Optional Room Air Kit  
If contaminants are found, you  
MUST:  
Model  
Description  
Kit Number  
KIT30022  
KIT30053  
• Remove products permanently.  
—OR—  
• Relocate air inlet and vent  
terminations to other areas.  
Filter Box Assembly  
90° Elbow with Screen  
400 - 801  
Air contamination  
Pool and laundry products and common household and hobby  
products often contain fluorine or chlorine compounds. When  
these chemicals pass through the boiler, they can form strong  
acids. The acid can eat through the boiler wall, causing serious  
damage and presenting a possible threat of flue gas spillage or  
boiler water leakage into the building.  
Please read the information given in Table 1A, page 11,  
listing contaminants and areas likely to contain them. If  
contaminating chemicals will be present near the location of  
the boiler combustion air inlet, have your installer pipe the  
boiler combustion air and vent to another location, per this  
manual.  
22  
Installation & Operation Manual  
4 Sidewall direct venting  
Vent/air termination – sidewall  
Figure 4-1A PVC/CPVC Sidewall Termination of Air and  
Vent  
Follow instructions below when  
determining vent location to avoid  
ƽ WARNING  
TO BOILER  
INTAKE AIR  
CONNECTION  
possibility of severe personal injury, death,  
or substantial property damage.  
FROM BOILER  
VENT PIPE  
CONNECTION  
12"  
A gas vent extending through an exterior  
ƽ WARNING  
wall shall not terminate adjacent to a  
MIN  
wall or below building extensions such  
as eaves, parapets, balconies, or decks.  
Failure to comply could result in severe  
personal injury, death, or substantial  
property damage.  
POSSIBLE ORIENTATIONS  
TO  
OVER-  
HANG  
VENT / AIR  
TERMINATION  
Do not connect any other appliance to  
ƽ WARNING  
12"  
MIN  
the vent pipe or multiple boilers to a  
common vent pipe. Failure to comply  
could result in severe personal injury,  
death, or substantial property damage.  
GRADE OR  
SNOW LINE  
Installation must comply with local  
Table 4A Sidewall Vent Kits  
NOTICE  
requirements and with the National  
Fuel Gas Code, ANSI Z223.1 for U.S.  
installations or CSA B149.1 for Canadian  
installations.  
Model Kit Number  
Vent Size  
400 - 601  
701 - 801  
KIT30046  
KIT30048  
4 inch vent  
6 inch vent  
Determine location  
If using the alternate sidewall termination:  
Locate the vent/air terminations using the following  
guidelines:  
3. The air piping must terminate in a down-turned elbow  
as shown in FIG. 4-1B. This arrangement avoids  
recirculation of flue products into the combustion air  
stream.  
1. The total length of piping for vent or air must not exceed  
the limits given in the General Venting Section on page  
21 of this manual.  
4. The vent piping must terminate in an elbow pointed  
outward or away from the air inlet, as shown in FIG. 4-1B.  
2. You must consider the surroundings when terminating  
the vent and air:  
Do not exceed the maximum lengths of the  
outside vent piping shown in FIG. 4-1B.  
Excessive length exposed to the outside could  
cause freezing of condensate in the vent pipe,  
resulting in potential boiler shutdown.  
a. Position the vent termination where vapors will  
not damage nearby shrubs, plants or air  
conditioning equipment or be objectionable.  
b. The flue products will form a noticeable plume as  
they condense in cold air. Avoid areas where the  
plume could obstruct window views.  
c. Prevailing winds could cause freezing of  
condensate and water/ice buildup where flue  
products impinge on building surfaces or plants.  
d. Avoid possibility of accidental contact of flue  
products with people or pets.  
ƽ WARNING  
Figure 4-1B Alternate PVC/CPVC Sidewall Termination  
of Air and Vent w/Field Supplied Fittings  
e. Do not locate the terminations where wind eddies  
could affect performance or cause recirculation,  
such as inside building corners, near adjacent  
buildings or surfaces, window wells, stairwells,  
alcoves, courtyards, or other recessed areas.  
Sidewall vent and air inlet terminations  
must terminate in the same pressure  
zone.  
ƽ WARNING  
f. Do not terminate above any door or window.  
Condensate can freeze, causing ice formations.  
g. Locate or guard vent to prevent condensate damage  
to exterior finishes.  
23  
Installation & Operation Manual  
4 Sidewall direct venting  
Vent/air termination – sidewall  
Figure4-2BAlternateStainlessSteelSidewallTermination  
Models 701 - 801 w/Field Supplied Fittings  
Figure 4-1C Alternate Stainless Steel Vent Termination  
- Typical Stainless Steel Sidewall Termination of Air  
and Vent Models 400 - 601 w/Field Supplied Fittings,  
Utilizing FasNSeal’s Hood Intake. Available Through  
FasNSeal Only  
TO BOILER INTAKE  
AIR CONNECTION  
BIRD SCREEN  
12" (305 MM) MIN  
15" (381 MM) MAX  
TO BOILER  
INTAKE AIR  
CONNECTION  
FROM BOILER VENT  
PIPE CONNECTION  
12" (305 MM) MIN  
15" (381 MM) MAX  
12" (305 MM) MIN  
FROM BOILER  
VENT PIPE  
CONNECTION  
GRADE OR  
SNOW LINE  
PVC/CPVC or ABS is acceptable air inlet pipe material.  
NOTICE  
5. Maintain clearances as shown in FIG.’s 4-1A thru 4-4B,  
pages 23 thru 25. Also maintain the following:  
a. Vent must terminate:  
12" (305 MM) MIN  
• At least 6 feet (1.8 m) from adjacent walls.  
• No closer than 12 inches (305 mm) below roof  
overhang.  
• At least 7 feet (2.1 m) above any public walkway.  
• At least 3 feet (.9 m) above any forced air intake  
within 10 feet (3 m).  
• No closer than 12 inches (305 mm) below or  
horizontally from any door or window or any other  
gravity air inlet.  
GRADE OR  
SNOW LINE  
Figure 4-1D Alternate PVC/CPVC/SS Vent Termination  
- Typical Stainless Steel Sidewall Termination of Air  
and Vent Models 400 - 601 w/Field Supplied Fittings,  
Utilizing 90° Elbow Intake  
TO BOILER  
INTAKE AIR  
CONNECTION  
b. Air inlet must terminate at least 12 inches (305 mm)  
above grade or snow line; at least 12 inches (305 mm)  
below the vent termination (FIG. 4-1B); and the vent  
pipe must not extend more than 24 inches (610 mm)  
vertically outside the building.  
FROM BOILER  
VENT PIPE  
CONNECTION  
12" MIN  
15" MAX  
c. Do not terminate closer than 4 feet (1.2 m)  
horizontally from any electric meter, gas meter,  
regulator, relief valve, or other equipment. Never  
terminate above or below any of these within 4 feet  
(1.2 m) horizontally.  
12" MIN  
BIRD SCREEN  
GRADE OR  
SNOW LINE  
6. Locate terminations so they are not likely to be damaged by  
foreign objects, such as stones or balls, or subject to buildup  
of leaves or sediment.  
Figure 4-2A Alternate PVC/CPVC Sidewall Termination  
Models 400 - 801 w/Field Supplied Fittings  
Figure 4-3A Clearance to Gravity Air Inlets  
BIRD SCREEN  
TO BOILER  
INTAKE AIR  
CONNECTION  
12" (305 MM) MIN  
15" (381 MM) MAX  
FROM BOILER  
VENT PIPE  
CONNECTION  
12"  
MIN.  
BIRD SCREEN  
VENT / AIR  
TERMINATION  
12" (305 MM) MIN  
12"  
MIN.  
12"  
MIN.  
GRADE OR  
SNOW LINE  
24  
Installation & Operation Manual  
4 Sidewall direct venting  
(continued)  
Vent/air termination – sidewall  
Prepare wall penetrations  
Figure 4-3B Alternate Clearance to Gravity Air  
Inlets  
w/Field Supplied Fittings  
1. Use the factory supplied wall plate as a template to locate  
the vent and air intake holes and mounting holes.  
Air pipe penetration:  
a. Cut a hole for the air pipe. Size the air pipe hole as  
close as desired to the air pipe outside diameter.  
Vent pipe penetration:  
a. Cut a hole for the vent pipe. For either combustible or  
noncombustible construction, size the vent pipe hole  
with at least a 1/2 inch clearance around the vent pipe  
outer diameter:  
12” (305 MM)  
MIN  
• 5½ inch hole (140 mm) hole for 4 inch (102 mm)  
vent pipe  
• 7½ inch hole (191 mm) hole for 6 inch (152 mm)  
vent pipe  
BIRD  
SCREEN  
(TYPICAL)  
12” (305 MM)  
MIN  
Drill 3/16" diameter holes for inserting the plastic anchors  
into the wall.  
12” (305 MM)  
MIN  
2. Install the vent and air intake piping through the wall into  
the vent plate openings. Seal all gaps between the pipes and  
wall. Use RTV silicone sealant to seal the air pipe. Use the  
cement/primer listed in Table 3A on page 18 to seal the vent  
pipe.  
Figure 4-4A Clearance to Forced Air Inlets  
IF LESS  
THAN 10’  
3. Mount and secure the vent plate to the wall using stainless  
steel screws. Seal around the plate to the wall assuring no  
air gaps.  
VENT / AIR  
TERMINATION  
36"  
MIN.  
4. Assemble the vent cap to the vent plate (see FIG. 4-4A).  
Insert the stainless steel screws into the vent cap screw hole  
openings and securely attach the vent cap to the vent plate.  
FORCED AIR  
INLET  
5. Seal all wall cavities.  
7' MIN. ABOVE ANY  
PUBLIC WALKWAY  
Figure 4-5A Sidewall Termination Assembly  
AIR PIPING  
Figure 4-4B Alternate Clearance to Forced Air Inlets  
w/Field Supplied Fittings  
VENT PIPING  
VENT PLATE  
IF LESS  
THAN 10’ (3 M)  
WALL PLATE  
VENT CAP  
GALVANIZED  
THIMBLE  
36” (914 MM)  
MIN  
FORCED AIR  
INLET  
BIRD  
SCREEN  
(TYPICAL)  
7’ (2.1 M) MIN ABOVE ANY  
PUBLIC WALKWAY  
25  
Installation & Operation Manual  
4 Sidewall direct venting  
Prepare wall penetrations (Alternate - Field 6. Stainless steel terminations are designed to penetrate walls  
with a thickness up to 9.25 inches of standard construction.  
Supplied Option)  
1. Air pipe penetration:  
Multiple vent/air terminations  
a. Cut a hole for the air pipe. Size the air pipe hole as  
1. When terminating multiple Knight XL’s terminate  
each vent/air connection as described in this manual  
(FIG. 4-6A).  
close as desired to the air pipe outside diameter.  
2. Vent pipe penetration:  
a. Cut a hole for the vent pipe. For either combustible  
or noncombustible construction, size the vent pipe  
hole with at least a 1/2 inch clearance around the vent  
pipe outer diameter:  
All vent pipes and air inlets must terminate  
ƽ WARNING  
at the same height to avoid possibility of  
severe personal injury, death, or substantial  
property damage.  
5½ inch hole (140 mm) hole for 4 inch (102 mm)  
vent pipe  
2. Place wall penetrations to obtain minimum clearance of  
12 inches (305 mm) between vent pipe and adjacent air  
inlet elbow, as shown in FIG. 4-6A for U.S. installations.  
For Canadian installations, provide clearances required  
by CSA B149.1 Installation Code.  
7½ inch hole (191 mm) hole for 6 inch (152 mm)  
vent pipe  
b. Insert a galvanized metal thimble in the vent pipe  
hole as shown in FIG. 4-5B.  
3. Use a sidewall termination plate as a template for correct  
location of hole centers.  
3. The air inlet of a Knight XL is part of a direct vent  
connection. It is not classified as a forced air intake with  
regard to spacing from adjacent boiler vents.  
4. Follow all local codes for isolation of vent pipe when passing  
through floors or walls.  
Figure 4-6A Multiple Vent Terminations (must also  
comply with Figure 4-1A)  
5. Seal exterior openings thoroughly with exterior caulk.  
Figure 4-5B A Typical Sidewall Termination Assembly  
- Models 400 - 801 PVC/CPVC or Stainless Steel  
12" MIN. BETWEEN EDGE OF AIR  
INLET AND ADJACENT VENT OUTLET  
VENT  
GALVANIZED  
SIDEWALL  
TERMINATION PLATE  
THIMBLE  
(WHEN REQUIRED BY LOCAL CODES)  
ELBOW  
AIR  
VENT  
PIPING  
AIR PIPING  
BIRD SCREEN  
ELBOW  
BIRD SCREEN  
VENT / AIR  
TERMINATION  
Termination and ttings  
1. Prepare the vent termination elbow and the air termination  
elbow (FIG. 4-5B) by inserting bird screens. Bird screens  
can be obtained locally.  
Figure 4-6B Alternate Multiple Vent Terminations  
w/Field Supplied Fittings (must also comply with  
Figure 4-1B)  
2. When completed, the air termination coupling must be  
oriented at least 12 inches (305 mm) below the vent  
termination and at least 12 inches (305 mm) above grade or  
snow line as shown in FIG. 4-1A, page 23.  
VENT  
12” (305 MM) MIN  
15” (381 MM) MAX  
3. Maintain the required dimensions of the finished  
termination piping as shown in FIG. 4-1A, page 23.  
4. Do not extend exposed vent pipe outside of building more  
than shown in this document. Condensate could freeze and  
block vent pipe.  
12” (305 MM) MIN. BETWEEN EDGE  
OF AIR PIPE AND ADJACENT VENT  
PIPE  
5. PVC/CPVC terminations are designed to accommodate any  
wall thickness of standard constructions per the directions  
found in this manual.  
AIR  
26  
Installation & Operation Manual  
4 Sidewall direct venting  
(continued)  
Sidewall termination – optional concentric vent: Models 400 - 601 Only  
Description and usage  
Lochinvar offers an optional concentric combustion air 3. You must consider the surroundings when terminating the  
and vent pipe termination kit (#CVK3007 for 4" (102 mm)  
diameter - Models 400 - 601). Both combustion air and vent  
pipes must attach to the termination kit. The termination kit  
must terminate outside the structure and must be installed as  
shown below in FIG. 4-7.  
vent and air:  
a. Position the vent termination where vapors will not  
damage nearby shrubs, plants or air conditioning  
equipment or be objectionable.  
b. The flue products will form a noticeable plume as  
they condense in cold air. Avoid areas where the  
plume could obstruct window views.  
Field supplied pipe and fittings are required to complete the  
installation.  
c. Prevailing winds could cause freezing of condensate  
and water/ice buildup where flue products impinge  
on building surfaces or plants.  
The required combustion vent pipe materials are listed in  
Table 3A, on page 18 of this manual.  
d. Avoid possibility of accidental contact of flue  
products with people or pets.  
Figure 4-7 Concentric Sidewall Termination - Models  
400 - 601  
OVERHANG  
OR ROOF  
f. Do not terminate above any door or window.  
Condensate can freeze, causing ice formations.  
g. Locate or guard vent to prevent condensate damage  
to exterior finishes.  
Figure 4-8 Kit Contents_CVK3007 - Models 400 - 601  
12" (305 MM)  
MIN  
RAIN CAP  
6" (152 MM) TO 4" (102 MM) REDUCER  
6" (152 MM) DIA.  
6" (152 MM) DIA.  
12" (305 MM)  
MIN  
4" (102 MM) DIA.  
GRADE / SNOW LINE  
"Y" CONCENTRIC  
FITTING  
Sidewall termination installation  
6" (152 MM) DIA.  
1. Determine the best location for the termination kit  
(see FIG. 4-7).  
"FLEXIBLE" PIPE  
COUPLING  
2. The total length of piping for vent or air must not exceed  
the limits given in the General Venting section on page 21  
of this manual.  
4. Cut one (1) hole (7 inch (178 mm) diameter for #CVK3007  
installations into the structure to install the termination kit.  
5. Partially assemble the concentric vent termination kit.  
Clean and cement using the procedures found in these  
instructions.  
a. Cement the Y concentric fitting to the larger kit pipe  
(FIG. 4-8).  
b. Cement the rain cap to the smaller diameter kit pipe  
(FIG. 4-8).  
27  
Installation & Operation Manual  
4 Sidewall direct venting  
Sidewall termination – optional concentric vent: Models 400 - 601 Only  
Figure 4-9 Concentric Vent Dimensional Drawing - Models 400 - 601  
"A"  
"B" DIA.  
"C" DIA.  
"D"  
3"  
(76 MM)  
"E"  
"G"  
"H" DIA.  
"B" DIA. PVC  
VENT / EXHAUST  
"F"  
A
B
C
D
E
F
G
H
60"  
4"  
6"  
(152 MM)  
21 1/8"  
10"  
7 5/8"  
3"  
(76 MM)  
6 5/8"  
(168 MM)  
(537 MM) (254 MM) (194 MM)  
(1524 MM) (102 MM)  
Instead of cementing the smaller pipe to  
the rain cap, a field-supplied stainless steel  
screw may be used to secure the two (2)  
components together when field disassembly  
is desired for cleaning (see FIG. 4-10).  
6. Install the Y concentric fitting and pipe assembly through  
the structure’s hole from an inside wall.  
NOTICE  
Do not allow insulation or other materials  
NOTICE  
to accumulate inside the pipe assembly  
when installing through the hole.  
When using the alternate screw assembly  
method, drill a clearance hole in the rain  
cap and a pilot hole in the vent pipe for  
the screw size being used. Failure to drill  
adequate holes may cause cracking of PVC  
components, allowing combustion products  
to be recirculated. Failure to follow this  
warning could result in personal injury or  
death.  
7. Install the rain cap and small diameter pipe assembly  
into the Y concentric fitting and large pipe assembly  
from an outside wall. Ensure small diameter pipe is  
fastened tightly into the rubber adapter for #CVK3007  
installations.  
ƽ WARNING  
8. Secure the assembly to the structure as shown in  
FIG. 4-11 using field-supplied metal strapping or  
equivalent support material.  
Ensure termination location clearance  
NOTICE  
Do not operate the appliance with the rain  
cap removed or recirculation of combustion  
products may occur. Water may also collect  
inside the larger combustion air pipe and  
flow to the burner enclosure. Failure to  
follow this warning could result in product  
damage or improper operation, personal  
injury, or death.  
ƽ WARNING  
dimensions are as shown in FIG. 4-7.  
If assembly needs to be extended to allow  
NOTICE  
sidewall thickness requirement, the two  
(2) pipes supplied in the kit may be  
replaced by using the same diameter,  
field-supplied standard schedule 40 PVC  
for CVK3007. Do not extend dimension  
D* more than 60 inches (1524 mm) (see  
FIG. 4-9).  
Figure 4-10 Rain Cap to Vent Pipe Alternate Assembly  
STAINLESS STEEL SCREW  
(FIELD SUPPLIED)  
If assembly depth needs to be reduced,  
NOTICE  
dimension D can be as short as possible.  
DRILL CLEARANCE HOLE IN  
RAIN CAP & PILOT HOLE  
IN VENT PIPE  
28  
Installation & Operation Manual  
4 Sidewall direct venting  
(continued)  
Sidewall termination – optional concentric vent: Models 400 - 601 Only  
Figure 4-11 Concentric Vent Sidewall Attachment  
STRAP  
(FIELD SUPPLIED)  
ELBOW  
(FIELD SUPPLIED)  
COMBUSTION AIR  
COMBUSTION AIR  
VENT  
VENT  
Multiventing sidewall terminations  
DO NOT use field-supplied couplings  
to extend pipes. Airflow restriction  
will occur and may cause intermittent  
operation.  
CAUTION  
When two (2) or more direct vent appliances are vented  
near each other, each appliance must be individually vented  
(see FIG. 4-12). NEVER common vent or breach vent this  
appliance. When two (2) or more direct vent appliances are  
vented near each other, two (2) vent terminations may be  
installed as shown in FIG. 4-12. It is important that vent  
terminations be made as shown to avoid recirculation of flue  
gases.  
9. Cement appliance combustion air and vent pipes to the  
concentric vent termination assembly. See FIG. 4-11  
for proper pipe attachment.  
10. Operate the appliance one (1) heat cycle to ensure  
combustion air and vent pipes are properly connected  
to the concentric vent termination connections.  
12"  
MINIMUM  
VENT  
COMBUSTION  
AIR  
Figure 4-12 Concentric Vent and Combustion Air Termination  
29  
Installation & Operation Manual  
5 Vertical direct venting  
Vent/air termination – vertical  
Follow instructions below when  
ƽ WARNING  
Rooftop vent and air inlet terminations  
must terminate in the same pressure zone,  
unless vertical vent sidewall air is set up as  
shown in the General Venting - Vertical  
Vent, Sidewall Air Section.  
ƽ WARNING  
determining vent location to avoid  
possibility of severe personal injury, death  
or substantial property damage.  
Do not connect any other appliance to the  
ƽ WARNING  
vent pipe or multiple boilers to a common  
Figure 5-1A PVC/CPVC Vertical Termination of Air and  
Vent  
vent pipe. Failure to comply could result in  
severe personal injury, death, or substantial  
property damage.  
ALTERNATE INTAKE LOCATIONS:  
INTAKE PIPES MAY BE LOCATED  
ANYWHERE WITHIN 24" (610 MM)  
OF VENT PIPE  
Installation must comply with local  
NOTICE  
requirements and with the National  
Fuel Gas Code, ANSI Z223.1 for U.S.  
installations or CSA B149.1 for Canadian  
installations.  
BIRD SCREEN  
(TYPICAL)  
VENT  
Determine location  
Locate the vent/air terminations using the following  
guidelines:  
COUPLING  
(FIELD SUPPLIED)  
6" (152 MM) MINIMUM  
ABOVE ROOF /  
SNOW LINE  
1. The total length of piping for vent or air must not exceed  
the limits given in the General Venting Section on page  
21 of this manual.  
VENT OUTLET  
COMBUSTION  
12" MINIMUM  
AIR  
ABOVE AIR INLET  
Figure 5-1B Stainless Steel Vertical Termination of Air  
and Vent  
2. The vent must terminate at least 3 feet above the highest  
place in which the vent penetrates the roof and at least  
2 feet above any part of a building within 10 horizontal  
feet.  
ALTERNATE INTAKE LOCATIONS:  
INTAKE PIPES MAY BE LOCATED  
ANYWHERE WITHIN 24” (610 MM)  
OF VENT PIPE  
3. The air piping must terminate in a down-turned 180°  
return pipe no further than 2 feet (.6 m) from the center  
of the vent pipe. This placement avoids recirculation of  
flue products into the combustion air stream.  
BIRD SCREEN  
(TYPICAL)  
VENT  
4. The vent piping must terminate in an up-turned coupling  
as shown in FIG. 5-1A. The top of the coupling must  
be at least 1 foot above the air intake. When the vent  
termination uses a rain cap as illustrated in FIG. 5-1B  
maintain at least 36" (914 mm) above the air inlet. The  
air inlet pipe and vent pipe can be located in any desired  
position on the roof, but must always be no further than  
2 feet (.6 m) apart and with the vent termination at least  
1 foot above the air intake.  
6" (152 MM) MINIMUM  
ABOVE ROOF /  
SNOW LINE  
COM,BUSTION  
AIR  
VENT OUTLET  
36” (914 MM) MINIMUM  
ABOVE AIR INLET  
5. Locate terminations so they are not likely to be damaged by  
foreign objects, such as stones or balls, or subject to buildup  
of leaves or sediment.  
30  
Installation & Operation Manual  
5 Vertical direct venting  
(continued)  
Vent/air termination – vertical  
Prepare roof penetrations  
Multiple vent/air terminations  
1. Air pipe penetration:  
1. When terminating multiple Knight XL boilers, terminate  
each vent/air connection as described in this manual  
(FIG. 5-2).  
a. Cut a hole for the air pipe. Size the air pipe hole as  
close as desired to the air pipe outside diameter.  
Terminate all vent pipes at the same height  
ƽ WARNING  
2. Vent pipe penetration:  
and all air pipes at the same height to  
a. Cut a hole for the vent pipe. For either combustible  
or noncombustible construction, size the vent pipe  
hole with at least a 1/2 inch clearance around the  
vent pipe outer diameter:  
avoid recirculation of flue products and  
the possibility of severe personal injury,  
death, or substantial property damage.  
5½ inch hole (140 mm) hole for 4 inch (102 mm)  
vent pipe  
7½ inch hole (191 mm) hole for 6 inch (152 mm)  
vent pipe  
2. Place roof penetrations to obtain minimum clearance  
of 12 inches (305 mm) between edge of air intake  
elbow and adjacent vent pipe of another boiler for U.S.  
installations (see FIG. 5-2). For Canadian installations,  
provide clearances required by CSA B149.1 Installation  
Code.  
b. Insert a galvanized metal thimble in the vent pipe  
hole (when required by local codes).  
3. The air inlet of a Knight XL boiler is part of a direct vent  
connection. It is not classified as a forced air intake with  
regard to spacing from adjacent boiler vents.  
3. Space the air and vent holes to provide the minimum  
spacing shown in FIG.’s 5-1A and 5-1B, page 30.  
4. Follow all local codes for isolation of vent pipe when  
passing through floors, ceilings, and roofs.  
Figure 5-2 Vertical Terminations with Multiple Boilers  
5. Provide flashing and sealing boots sized for the vent pipe  
and air pipe.  
12" (305 MM) MINIMUM  
VERTICALLY FROM VENT  
OUTLET TO ANY AIR INLET  
VENT  
Termination and ttings  
AIR  
12" (305 MM) MINIMUM FROM EDGE  
OF AIR INTAKE PIPE TO ADJACENT  
VENT PIPE FROM ANOTHER BOILER  
VENT  
1. Prepare the vent termination coupling and the air  
termination elbow (FIG.’s 5-1A and 5-1B) by inserting  
bird screens. Bird screens should be obtained locally.  
AIR  
2. The air piping must terminate in a down-turned 180°  
return bend as shown in FIG.’s 5-1A and 5-1B. Locate the  
air inlet pipe no further than 2 feet (.6 m) from the center  
of the vent pipe. This placement avoids recirculation of  
flue products into the combustion air stream.  
Figure 5-3 Alternate Vertical Terminations with Multiple  
Boilers  
3. The vent piping must terminate in an up-turned coupling  
as shown in FIG. 5-1A. The top of the coupling must be  
at least 1 foot (.3 m) above the air intake. When the vent  
termination uses a rain cap as illustrated in FIG. 5-1B  
maintain at least 36" (914 mm) above the air inlet. The  
air inlet pipe and vent pipe can be located in any desired  
position on the roof, but must always be no further than  
2 feet (.6 m) apart and with the vent termination at least  
1 foot (.3 m) above the air intake.  
VENT  
VENT  
12" (305 MM) MINIMUM  
VERTICALLY FROM VENT  
OUTLET TO ANY AIR INLET  
AIR  
4. Maintain the required dimensions of the finished  
termination piping as shown in FIG.’s 5-1A and 5-1B.  
AIR  
5. Do not extend exposed vent pipe outside of building  
more than shown in this document. Condensate could  
freeze and block vent pipe.  
31  
Installation & Operation Manual  
5 Vertical direct venting  
Vertical termination – optional concentric vent: Models 400 - 601 Only  
Description and usage  
2. Cut one (1) hole (7 inch (178 mm) diameter for #CVK3007  
Lochinvar offers an optional concentric combustion air and  
vent pipe termination kit. Both combustion air and vent  
pipes must attach to the termination kit. The termination kit  
must terminate outside the structure and must be installed as  
shown in FIG. 5-4.  
installations) into the structure to install the termination  
kit.  
3. Partially assemble the concentric vent termination kit.  
Clean and cement following the cleaning procedures in  
these instructions.  
Field supplied pipe and fittings are required to complete the  
installation.  
a. Cement the Y concentric fitting to the larger  
diameter kit pipe (see FIG. 4-8, page 27).  
b. Cement rain cap to the smaller diameter kit pipe (see  
FIG. 4-8, page 27).  
The required combustion vent pipe fittings are listed in  
Table 3A, on page 18 of this manual.  
Vertical termination installation  
Instead of cementing the smaller pipe  
NOTICE  
to the rain cap, a field supplied stainless  
steel screw may be used to secure the  
two (2) components together when field  
disassembly is desired for cleaning (see  
FIG. 4-10, page 28).  
1. See Section 5, Vertical Direct Venting - Determine  
Location (where applicable).  
Figure 5-4 Concentric Vertical Termination  
When using the alternate screw assembly  
ƽ WARNING  
method, drill a clearance hole in the rain  
cap and a pilot hole in the vent pipe for  
the screw size being used. Failure to drill  
adequate holes may cause cracking of PVC  
components, allowing combustion products  
to be recirculated. Failure to follow this  
warning could result in personal injury or  
death.  
VENT  
COMBUSTION  
AIR  
12" (305 MM) (18" (457 MM)  
FOR CANADA) MINIMUM  
CLEARANCE ABOVE HIGHEST  
ANTICIPATED SNOW  
LEVEL. MAXIMUM OF  
24" (610 MM) ABOVE ROOF.  
Figure 5-5 Do Not Install U-Bend to Rain Cap  
32  
Installation & Operation Manual  
5 Vertical direct venting  
(continued)  
Vertical termination – optional concentric vent: Models 400 - 601 Only  
Do not operate the appliance with  
DO NOT use field-supplied couplings  
to extend pipes. Airflow restriction will  
occur.  
ƽ WARNING  
CAUTION  
the rain cap removed or recirculation  
of combustion products may occur.  
Water may also collect inside the larger  
combustion air pipe and flow to the  
burner enclosure. Failure to follow this  
warning could result in product damage  
or improper operation, personal injury,  
or death.  
6. Install the rain cap and the small diameter pipe assembly  
into the roof penetration assembly. Ensure the small  
diameter pipe is fastened tightly into the rubber adapter  
for #CVK3007 installations.  
7. Cement the appliance combustion air and vent pipes to  
the concentric vent termination assembly. See FIG. 5-6  
for proper pipe attachment.  
4. Install the Y concentric fitting pipe assembly up through  
the structure’s hole and field supplied roof boot/flashing.  
Do not allow insulation or other materials  
NOTICE  
8. Operate the appliance through one (1) heat cycle to ensure  
combustion air and vent pipes are properly connected to  
the concentric vent termination connections.  
to accumulate inside the pipe assembly  
when installing through the hole.  
5. Secure the assembly to the roof structure as shown  
below in FIG. 5-6 using field supplied metal strapping or  
equivalent support material.  
Multiventing vertical terminations  
When two (2) or more direct vent appliances are vented  
near each other, each appliance must be individually vented  
(see FIG. 5-7). NEVER common vent or breach vent this  
appliance. When two (2) or more direct vent appliances  
are vented near each other, two (2) vent terminations may  
be installed as shown in FIG. 5-7. It is important that vent  
terminations be made as shown to avoid recirculation of flue  
gases.  
Figure 5-6 Concentric Vent Roof Installation  
VENT  
12" (305 MM) (18" (457 MM) FOR CANADA)  
MINIMUM CLEARANCE ABOVE HIGHEST  
ANTICIPATED SNOW LEVEL. MAXIMUM OF  
24” (610 MM) ABOVE ROOF.  
COMBUSTION  
AIR  
ROOF BOOT /  
FLASHING  
(FIELD SUPPLIED)  
Figure 5-7 Concentric Vent and Combustion Air Vertical  
Termination  
SUPPORT  
(FIELD SUPPLIED)  
12”  
MINIMUM  
ELBOW  
(FIELD SUPPLIED)  
COMBUSTION  
AIR  
COMBUSTION  
AIR (TYPICAL)  
VENT  
Ensure termination height is above the  
roof surface or anticipated snow level  
(12 inches (305 mm) in U.S.A. or 18  
inches (457 mm) in Canada) as shown in  
FIG. 5-4, page 32.  
NOTICE  
NOTICE  
12” (18” FOR CANADA)  
MINIMUM CLEARANCE  
ABOVE HIGHEST  
ANTICIPATED SNOW  
LEVEL. MAXIMUM OF  
24” ABOVE ROOF.  
If assembly is too short to meet height  
requirement, the two (2) pipes supplied  
in the kit may be replaced by using the  
same diameter, field supplied standard  
schedule 40 PVC for CVK3007. Do not  
extend dimension D* more than 60 inches  
(1524 mm) (see FIG. 4-9, page 28).  
33  
Installation & Operation Manual  
5 Vertical direct venting  
Alternate vertical concentric venting  
This appliance may be installed with a concentric vent  
arrangement where the vent pipe is routed through an  
existing unused venting system; or by using the existing  
unused venting system as a chase for vent and combustion  
air routing.  
Figure 5-8 Concentric Vent Example 1  
FLUE EXHAUST  
SEAL  
Concentric Venting Arrangement  
COMBUSTION AIR  
The venting is to be vertical through the roof. The annular  
space between the O.D. of the vent pipe and the I.D. of the  
existing unused venting system is utilized for the combustion  
air source.  
AIR INLET  
W/ SCREEN  
12"  
MIN.  
The minimum size of the existing vent system required to  
achieve enough annular space for combustion air can be  
found in Table 5A.  
EXISTING  
SEAL  
SEALED  
CAP  
The upper and lower termination as well as any other unsealed  
joints in the existing vent system must be sealed to ensure that  
all combustion air is drawn from under the vent cap as shown  
in FIG.’s 5-8 and 5-9.  
FLUE OUTLET  
Approved venting materials must be used as specified in  
Table 3A on page 18.  
*For concept illustration only. Individual installations  
may vary due to job site specic equipment.  
Follow all vent / air termination and clearance requirements  
per this section to the appropriate example. Installation must  
comply with local requirements and with the National Fuel  
Gas Code.  
Figure 5-9 Concentric Vent Example 2  
FLUE EXHAUST  
SEAL  
The maximum allowable equivalent vent and air intake  
lengths for this venting arrangement are to be determined  
from the General Venting Section.  
If an existing unused venting system is converted for use  
with this method of concentric venting, the installer must  
ensure that the existing venting system is clean and free from  
particulate contamination that will harm this appliance and  
cause increased nuisance calls or maintenance. See Table 1A  
on page 11 for a list of corrosive contaminants and sources.  
COMBUSTION AIR  
AIR INLET  
W/ SCREEN  
SEAL  
Two example scenarios of a concentric venting arrangement  
are shown for illustrative purposes in FIG.’s 5-8 and 5-9.  
EXISTING  
Table 5A Alternate Vertical Concentric Vent / Chase Sizes  
SEAL  
SEALED  
CAP  
Vent / Air Minimum Existing  
Model  
Inlet Size  
Vent / Chase Size  
400 - 601  
701 - 801  
4"  
6"  
7"  
FLUE OUTLET  
10"  
*For concept illustration only. Individual installations  
may vary due to job site specic equipment.  
34  
Installation & Operation Manual  
5 Vertical direct venting  
(continued)  
Existing vent as a chase  
Follow all existing termination and clearance requirements and  
allowable pipe lengths. Use only approved venting materials  
listed in the General Venting Section of this manual.  
Figure 5-10 Existing Vent as a Chase  
FLUE EXHAUST  
AIR INLET  
SEAL  
EXISTING  
CAP  
SEAL  
FLUE OUTLET  
*For concept illustration only. Individual installations  
may vary due to job site specic equipment.  
35  
Installation & Operation Manual  
6 Hydronic piping  
System water piping methods  
General piping information  
The Knight XL is designed to function in a closed loop Basic steps are listed below along with illustrations on the  
pressurizedsystemnotlessthan12psi(83kPa). Atemperature following pages (FIG.’s 6-7 through 6-11), which will guide you  
and pressure gauge is included to monitor system pressure through the installation of the Knight XL (reference FIG.’s 6-4A  
and outlet temperature and should be located on the boiler and 6-4B).  
outlet.  
1. Connect the system return marked “Inlet”.  
It is important to note that the boiler has a minimal amount  
2. Connect the system supply marked “Outlet”.  
of pressure drop which must be figured in when sizing  
3. Install purge and balance valve or shutoff valve and drain  
on system return to purge air out of each zone.  
the circulators. Each boiler installation must have an air  
elimination device, which will remove air from the system.  
Install the boiler so the gas ignition system components  
are protected from water (dripping, spraying, etc.) during  
appliance operation or basic service of circulator replacement,  
valves, and others.  
4. Install a backflow preventer on the cold feed make-up water  
line.  
5. Install a pressure reducing valve on the cold feed make-up  
water line, (15 psi (103 kPa) nominal). Check temperature  
and pressure gauge (shipped separately), which should read  
a minimum pressure of 12 psi (83 kPa).  
Observe a minimum of 1/4 inch (6 mm) clearance around all  
un-insulated hot water pipes when openings around the pipes  
are not protected by non-combustible materials.  
6. Install a circulator as shown on the piping diagrams in this  
section. Make sure the circulator is properly sized for the  
system and friction loss.  
Low water cutoff device  
On a boiler installed above radiation level, some states and  
local codes require a low water cutoff device at the time of  
installation.  
7. Install an expansion tank on the system supply. Consult the  
tank manufacturer’s instruction for specific information  
relating to tank installation. Size the expansion tank for the  
required system volume and capacity.  
Chilled water system  
8. Install an air elimination device on the system supply.  
If the boiler supplies hot water to heating coils in air handler  
units, flow control valves or other devices must be installed to  
prevent gravity circulation of heater water in the coils during  
the cooling cycle. A chilled water medium must be piped in  
parallel with the heater.  
9. Install a drain valve at the lowest point of the system.  
Note: The boiler cannot be drained completely of water  
without purging the unit with an air pressure of 15 psi  
(103 kPa).  
10. This appliance is supplied with a relief valve sized in  
accordance with ASME Boiler and Pressure Vessel Code,  
Section IV (“Heating Boilers”). Pipe the discharge of the  
safety relief valve to prevent injury in the event of pressure  
relief. Pipe the discharge to a drain. Provide piping that is  
the same size as the safety relief valve outlet. Never block  
the outlet of the safety relief valve.  
Freeze protection  
Freeze protection for new or existing systems must use  
glycol that is specially formulated for this purpose. This  
includes inhibitors, which prevent the glycol from attacking  
the metallic system components. Make certain to check that  
the system fluid is correct for the glycol concentration and  
inhibitor level. The system should be tested at least once  
a year and as recommended by the producer of the glycol  
solution. Allowance should be made for the expansion of the  
glycol solution in the system piping.  
The relief valve, tee and any other necessary  
ƽ WARNING  
fittings are shipped in the install kit with the  
boiler and are to be field installed (FIG.’s 6-1  
and 6-2).  
11. On any pre-existing system, it is good practice to install  
a field supplied strainer to prevent damage to the heat  
exchanger.  
Use only inhibited propylene glycol  
ƽ WARNING  
solutions, which are specifically formulated  
for hydronic systems. Ethylene glycol is  
toxic and can attack gaskets and seals used  
in hydronic systems.  
See the piping illustrations included in this section, FIG.’s 6-7  
and 6-11 for suggested guidelines in piping the Knight XL.  
Please note that these illustrations are  
NOTICE  
meant to show system piping concept only,  
the installer is responsible for all equipment  
and detailing required by local codes.  
36  
Installation & Operation Manual  
6 Hydronic piping  
(continued)  
Flowswitch,reliefvalveandtemperature  
and pressure gauge installation  
Figure 6-1 Flow Switch, Relief Valve and Temperature and  
Pressure Gauge Installation_Models 400 - 501  
Basic steps are listed below to guide you through the  
installation of the flow switch, relief valve, and temperature  
and pressure gauge provided with the unit.  
1. For Models 400 - 501 install the close nipple on the  
outlet connection of the heat exchanger. Install the tee  
with the 3/4 inch fitting positioned vertically and on  
the top as shown in FIG. 6-1. For Models 601 - 801  
install the tee directly to the outlet connection of the  
heat exchanger with the 3/4 inch fitting positioned  
vertically and on the top (see FIG. 6-2).  
RELIEF VALVE  
FLOW SWITCH  
PADDLE  
TEMPERATURE AND  
PRESSURE  
GAUGE  
2. For Models 701 - 801 install the 3/4 inch close nipple  
in the tee. Install the relief valve on the 3/4 inch close  
nipple (FIG. 6-2). For Models 400 - 601 install the  
relief valve directly into the 3/4 inch fitting on the tee  
(FIG. 6-1).  
TEE WITH FITTING ON TOP  
(FIELD PROVIDED)  
CLOSE NIPPLE (FIELD PROVIDED)  
TEE WITH 1” FITTING ON TOP  
3. Install the close nipple on the downstream side of  
the relief valve tee (FIG. 6-1).  
CLOSE NIPPLE  
TEE WITH 3/4” FITTING ON TOP  
CLOSE NIPPLE  
4. Install the tee with the 1 inch fitting positioned  
vertically and on the top (FIG. 6-1).  
5. Attach paddle #3 to the flow switch per the  
manufacturer’s instructions.  
Figure 6-2 Flow Switch, Relief Valve and Temperature and  
Pressure Gauge Installation_Models 601 - 801  
6. Install the assembled flow switch into the 1 inch fitting  
of the tee installed in Step 4 (see FIG. 6-1).  
7. Install a field provided close nipple on the downstream  
side of the flow switch (see FIG.’s 6-1 and 6-2).  
RELIEF VALVE  
8. Install a field provided tee with the gauge fitting  
positioned vertically and on the top (FIG.’s 6-1 and  
6-2)  
FLOW SWITCH  
PADDLE  
9. Install the temperature and pressure gauge provided  
with the unit into the top fitting of the tee (a bushing  
may be necessary) installed in Step 8 (FIG.’s 6-1 and  
6-2).  
TEMPERATURE AND  
PRESSURE  
GAUGE  
Be sure to install the flow switch so  
NOTICE  
TEE WITH FITTING ON TOP  
(FIELD PROVIDED)  
that the arrow on the flow switch is  
pointing in the direction of the flow  
(see FIG. 6-3).  
CLOSE NIPPLE (FIELD PROVIDED)  
TEE WITH 1” FITTING ON TOP  
CLOSE NIPPLE  
TEE WITH 3/4” FITTING ON TOP  
CLOSE NIPPLE  
37  
Installation & Operation Manual  
6 Hydronic piping  
Flow switch adjustment  
Near boiler piping components  
Refer to Table 6A for the proper setting of the sensitivity  
screw. For reference, the position of the screw prior to setting  
should be turned clockwise with a Phillips driver until it stops  
(FIG. 6-3). Proceed to turn the screw counterclockwise the  
amount of turns listed in Table 6A based on the model.  
1. Boiler system piping:  
Boiler system piping MUST be sized per the pipe  
requirements listed in Table 6B. Reducing the pipe size  
can restrict the flow rate through the boiler, causing  
inadvertent high limit shutdowns and poor system  
performance. Flow rates are based on 20 feet (6 m) of  
piping, 4 - 90° elbows, and 2 - fully ported ball valves.  
Consult the manufacturer’s instructions for wiring the flow  
switch to your system.  
2. Boiler system circulating pump:  
Field supplied. The boiler circulating pump should be  
based on 20 feet (6 m) of piping, 4 - 90° elbows, and  
2 - fully ported ball valves.  
Table 6A Paddle Size / Sensitivity Screw Adjustment  
SENSITIVITY SCREW  
MODEL  
PADDLE SIZE  
ADJUSTMENT  
Note: Paddles are included with the ow switch.  
3. Domestic hot water circulating pump:  
Field supplied. The pump MUST be sized to meet  
the specified minimum flow requirements listed in  
FIG.’s 6-5 and 6-6. Consult the indirect water heater  
operating guide to determine flow characteristics for the  
selected product used.  
400  
501  
601  
701  
801  
#3  
#3  
#3  
#3  
#3  
7½ turns  
5½ turns  
7¼ turns  
5¼ turns  
3¼ turns  
Turn the sensitivity screw clockwise to  
increase the flow rate required to activate  
the switch. Turn the sensitivity screw  
counterclockwise to decrease the flow rate  
required to activate the switch.  
4. Variable speed boiler system circulator:  
Knight boilers are capable of controlling a variable  
speed boiler system circulator. Variable speed circulators  
MUST be sized to meet the specified minimum flow  
requirements listed in FIG.’s 6-5 and 6-6 on page 40 at  
full speed.  
NOTICE  
Figure 6-3 Flow Switch Adjustment  
NORMALLY  
OPEN  
5. Boiler isolation valves:  
Field supplied. Full port ball valves are required. Failure  
to use full port ball valves could result in a restricted flow  
rate through the boiler.  
SENSITIVITY  
ADJUSTMENT  
6. Check valves:  
Field supplied. Check valves are recommended for  
installation as shown in FIG.’s 6-7 through 6-11. Failure  
to install check valves could result in a reverse flow  
condition during pump(s) off cycle.  
GROUND  
7. Domestic indirect hot water isolation valves:  
Field supplied. Full port ball valves are required. Failure  
to use full port ball valves could result in a restricted flow  
rate through the boiler.  
NORMALLY  
CLOSED  
COMMON  
8. Anti-scald mixing valve:  
Field supplied. An anti-scald mixing valve is  
recommended when storing domestic hot water above  
115°F (46°C).  
9. Unions:  
Field supplied. Recommended for unit serviceability.  
10. Temperature and pressure gauge:  
Factory supplied. The temperature and pressure gauge is  
shipped loose. It is the responsibility of the contractor to  
install the temperature and pressure gauge on the boiler  
water outlet.  
11. Pressure relief valve:  
38  
Factory supplied. The pressure relief valve is sized to  
ASME specifications.  
Installation & Operation Manual  
6 Hydronic piping  
(continued)  
12. Boiler purge valve:  
Figure 6-4B Near Boiler Piping w/Low Loss Header  
Field supplied. The boiler purge valve is used to  
remove entrapped air from the heat exchanger during  
start-up.  
SYSTEM PUMP  
SYSTEM SENSOR  
AIR SEPARATOR  
DRAIN  
(TYPICAL)  
AIR VENT VALVE  
13. System temperature sensor:  
LOW LOSS HEADER  
(TYPICAL)  
Lochinvar supplies a system temperature sensor. The  
sensor is to be installed in the heating loop downstream  
from the boiler hot water piping and heating loop  
junction. The sensor should be located far enough  
downstream to sense system diluted water temperature.  
EXPANSION TANK  
FAST FILL VALVE  
INDIRECT  
DOMESTIC  
DRAIN  
HOT WATER  
TANK  
VALVE  
14. Y-Strainer:  
Field supplied. A Y-strainer or equivalent multipurpose  
strainer is recommended at the inlet of the heat exchanger  
to remove system particles from older hydronic systems  
and protect newer systems.  
Y-STRAINER  
(RECOMMENDED)  
BOILER PUMP  
Circulator sizing  
The Knight XL heat exchanger does have a pressure drop,  
which must be considered in your system design. Refer to the  
graphs in FIG’s 6-5 and 6-6 for pressure drop through the  
Knight XL heat exchanger.  
Near boiler piping connections  
TO FLOOR  
DRAIN  
Figure 6-4A Near Boiler Piping w/Y-Strainer  
Variable speed pump option  
Variable speed pump setup  
Before operation, ensure the following:  
DOMESTIC HOT  
WATER PUMP  
INDIRECT  
DIRT SEPARATOR  
SYSTEM SENSOR  
SYSTEM PUMP  
-
Pump is set for an input signal of 0 - 10VDC  
by the dip switches on the pump control  
DOMESTIC  
HOT WATER  
TANK  
-
Pump is set for external signal control  
(if applicable)  
-
-
Pump is set for linear output (if applicable)  
Y-STRAINER  
(RECOMMENDED)  
If pump does not come equipped with a  
0 - 10 VDC input option, an optional module  
will be required from the vendor  
BOILER PUMP  
TO FLOOR  
DRAIN  
39  
Installation & Operation Manual  
6 Hydronic piping  
Figure 6-5 Pressure Drop vs. Flow - Models 400 and 501  
Pressure Drop vs Flow  
(Includes Boiler Secondary Piping)  
20  
18  
16  
14  
12  
10  
8
KBN501  
KBN400  
6
4
2
0
0
5
10  
15  
20  
25  
30  
35  
40  
45  
Flow Rate (GPM)  
Figure 6-6 Pressure Drop vs. Flow - Models 601 thru 801  
Pressure Drop vs Flow  
(Includes Boiler Secondary Piping)  
60  
50  
40  
30  
20  
10  
0
KBN801  
KBN701  
KBN601  
0
10  
20  
30  
40  
50  
60  
70  
80  
90  
Flow Rate (GPM)  
Table 6B Sizing Information for Temperature Rise Applications_20°F, 25°F, 30°F and 35°F  
TEMPERATURE RISE APPLICATIONS  
20°F  
25°F  
30°F  
35°F  
MINIMUM  
PIPE  
Model  
GPM  
FT/HD  
GPM  
FT/HD  
GPM  
FT/HD  
GPM  
FT/HD  
SIZE  
400  
501  
601  
701  
801  
1 1/2"  
1 1/2"  
2"  
37  
46  
55  
65  
74  
21  
23  
31  
30  
33  
30  
37  
44  
52  
60  
14  
16  
22  
20  
23  
26  
32  
38  
45  
51  
11  
13  
18  
16  
18  
21  
26  
32  
37  
42  
8
10  
13  
11  
12  
2"  
2"  
40  
Installation & Operation Manual  
6 Hydronic piping  
(continued)  
Figure 6-7 Single Boiler - Multiple Temperatures  
TEMPERATURE  
LOOP 3  
TEMPERATURE  
LOOP 2  
TEMPERATURE  
LOOP 1  
AIR SEPARATOR  
MAKE UP WATER  
PRESSURE  
GAUGE  
Y-STRAINER  
(RECOMMENDED)  
BACK FLOW  
PREVENTER  
FLOW CHECK  
DRAIN POINT  
(TYPICAL)  
VALVE (TYPICAL)  
BOILER CIRCULATOR  
BALL VALVE  
(TYPICAL)  
PRESSURE  
RELIEF  
VALVE  
PRESSURE  
EXPANSION  
TANK  
REDUCING  
VALVE  
INDIRECT DHW  
TANK  
HOT WATER OUT  
UNION (TYPICAL)  
ANTI-SCALD  
MIXING VALVE  
DOMESTIC  
DRAIN  
HOT WATER  
CIRCULATOR  
COLD WATER IN  
TEMPERATURE / PRESSURE  
GAUGE  
BOILER  
Mixing valves are required for the protection of low temperature loops.  
CAUTION  
NOTICE  
Please note that these illustrations are meant to show system piping concept only, the installer is responsible  
for all equipment and detailing required by local codes.  
41  
Installation & Operation Manual  
6 Hydronic piping  
Figure 6-8 Single Boiler - Primary/Secondary Piping  
AIR SEPARATOR  
MAY SUBSTITUTE  
LOW LOSS HEADER  
DRAIN POINT  
(TYPICAL)  
NOT TO EXCEED 4 PIPE DIA OR MAX. OF 12" APART  
SYSTEM SUPPLY SENSOR  
(WHEN USED)  
BALL VALVE  
(TYPICAL)  
SYSTEM CIRCULATOR  
PRESSURE GAUGE  
EXPANSION TANK  
Y-STRAINER  
(RECOMMENDED)  
BOILER CIRCULATOR  
MAKE UP WATER  
BACK FLOW  
PREVENTER  
PRESSURE REDUCING  
VALVE  
INDIRECT DHW  
TANK  
ANTI-SCALD  
MIXING VALVE  
HOT WATER OUT  
DOMESTIC  
HOT WATER  
CIRCULATOR  
BOILER  
PRESSURE RELIEF  
UNION (TYPICAL)  
COLD WATER IN  
TEMPERATURE / PRESSURE  
GAUGE  
VALVE  
DRAIN  
FLOW CHECK  
VALVE (TYPICAL)  
Indirect water heaters are capable of transferring a limited number of Btu’s into the water. Ensure boiler  
output does not not exceed indirect water heater transfer capabilities.  
CAUTION  
NOTICE  
Please note that these illustrations are meant to show system piping concept only, the installer is responsible  
for all equipment and detailing required by local codes.  
System flow should always remain higher than the required flow for the boiler(s) when the boiler(s) is in  
operation to prevent short cycling and high limit issues.  
NOTICE  
42  
Installation & Operation Manual  
6 Hydronic piping  
(continued)  
Figure 6-9 Multiple Boilers - Multiple Temperatures  
Number of Units  
2
3
4
5
6
7
8
Model  
Manifold Pipe Sizes in Inches (mm)  
2 1/2 (64) 3 (76) 3 1/2 (89) 4 (102) 4 (102) 5 (127) 6 (152)  
3 (76) 3 1/2 (89) 4 (102) 5 (127) 5 (127) 6 (152) 6 (152)  
3 1/2 (89) 4 (102) 5 (127) 5 (127) 6 (152) 6 (152) 8 (203)  
400  
501  
601  
3 1/2 (89) 5 (127) 5 (127) 6 (152) 6 (152) 8 (203) 8 (203)  
4 (102) 5 (127) 5 (127) 6 (152) 8 (203) 8 (203) 8 (203)  
701  
801  
TEMPERATURE  
LOOP 3  
TEMPERATURE  
LOOP 2  
TEMPERATURE  
LOOP 1  
AIR SEPARATOR  
MAKE UP WATER  
PRESSURE  
GAUGE  
Y-STRAINER  
(RECOMMENDED)  
FLOW CHECK  
BALL VALVE  
(TYPICAL)  
VALVE (TYPICAL)  
BOILER CIRCULATOR  
BACK FLOW  
PREVENTER  
PRESSURE  
REDUCING  
VALVE  
DRAIN POINT  
(TYPICAL)  
PRESSURE  
RELIEF  
VALVE  
EXPANSION  
TANK  
INDIRECT DHW  
TANK  
DRAIN  
HOT WATER OUT  
TEMPERATURE /  
BOILER 2  
ANTI-SCALD  
PRESSURE GAUGE  
MIXING VALVE  
UNION (TYPICAL)  
COLD WATER IN  
DOMESTIC  
HOT WATER  
CIRCULATOR  
BOILER 1  
Indirect water heaters are capable of transferring a limited number of Btu’s into the water. Ensure boiler  
output does not not exceed indirect water heater transfer capabilities.  
CAUTION  
Mixing valves are required for the protection of low temperature loops.  
CAUTION  
NOTICE  
Please note that these illustrations are meant to show system piping concept only, the installer is responsible  
for all equipment and detailing required by local codes.  
43  
Installation & Operation Manual  
6 Hydronic piping  
Figure 6-10 Multiple Boilers - Primary/Secondary Piping  
Number of Units  
2
3
4
5
6
7
8
Model  
Manifold Pipe Sizes in Inches (mm)  
2 1/2 (64) 3 (76) 3 1/2 (89) 4 (102) 4 (102) 5 (127) 6 (152)  
3 (76) 3 1/2 (89) 4 (102) 5 (127) 5 (127) 6 (152) 6 (152)  
3 1/2 (89) 4 (102) 5 (127) 5 (127) 6 (152) 6 (152) 8 (203)  
400  
501  
601  
701  
801  
3 1/2 (89) 5 (127) 5 (127) 6 (152) 6 (152) 8 (203) 8 (203)  
4 (102) 5 (127) 5 (127) 6 (152) 8 (203) 8 (203) 8 (203)  
BALL VALVE  
(TYPICAL)  
MAY SUBSTITUTE  
LOW LOSS HEADER  
AIR SEPARATOR  
DRAIN POINT  
(TYPICAL)  
SYSTEM SUPPLY SENSOR  
(WHEN USED)  
SYSTEM CIRCULATOR  
MAKE UP WATER  
Y-STRAINER  
(TYPICAL)  
(RECOMMENDED)  
EXPANSION  
TANK  
BACK FLOW  
PREVENTER  
PRESSURE REDUCING  
VALVE  
BOILER 4  
PRESSURE GAUGE  
(MEMBER 3)  
INDIRECT DHW  
TANK  
BOILER 3  
(MEMBER 2)  
ANTI-SCALD  
MIXING VALVE  
HOT WATER OUT  
BOILER 2  
(MEMBER 1)  
BOILER 1  
(LEADER)  
DOMESTIC  
HOT WATER  
CIRCULATOR  
BOILER CIRCULATOR  
(TYPICAL)  
PRESSURE RELIEF  
VALVE  
COLD WATER IN  
UNION (TYPICAL)  
DRAIN  
FLOW CHECK  
TEMPERATURE /  
PRESSURE GAUGE  
VALVE (TYPICAL)  
Indirect water heaters are capable of transferring a limited number of Btu’s into the water. Ensure boiler  
output does not not exceed indirect water heater transfer capabilities.  
CAUTION  
NOTICE  
Please note that these illustrations are meant to show system piping concept only, the installer is responsible  
for all equipment and detailing required by local codes.  
System flow should always remain higher than the required flow for the boiler(s) when the boiler(s) is in  
operation to prevent short cycling and high limit issues.  
NOTICE  
44  
Installation & Operation Manual  
6 Hydronic piping  
(continued)  
Figure 6-11 Single Boiler - Multiple Temperatures with DHW Piped as a Zone  
TEMPERATURE  
TEMPERATURE  
LOOP 2  
LOOP 3  
TEMPERATURE  
LOOP 1  
AIR SEPARATOR  
PRESSURE  
BALL VALVE  
(TYPICAL)  
GAUGE  
MAKE UP WATER  
Y-STRAINER  
(RECOMMENDED)  
FLOW CHECK  
VALVE (TYPICAL)  
BACK FLOW  
PREVENTER  
PRESSURE  
RELIEF  
BOILER CIRCULATOR  
VALVE  
PRESSURE  
REDUCING  
VALVE  
DRAIN POINT  
(TYPICAL)  
EXPANSION  
TANK  
INDIRECT DHW  
TANK  
HOT WATER OUT  
ANTI-SCALD  
UNION (TYPICAL)  
DRAIN  
MIXING VALVE  
COLD WATER IN  
DOMESTIC  
HOT WATER  
CIRCULATOR  
TEMPERATURE / PRESSURE  
GAUGE  
BOILER  
Indirect water heaters are capable of transferring a limited number of Btu’s into the water. Ensure boiler  
output does not not exceed indirect water heater transfer capabilities.  
CAUTION  
Mixing valves are required for the protection of low temperature loops.  
CAUTION  
NOTICE  
Please note that these illustrations are meant to show system piping concept only, the installer is responsible  
for all equipment and detailing required by local codes.  
Please note that the installer is responsible for ensuring DHW prioritization when piped as a zone.  
NOTICE  
45  
Installation & Operation Manual  
7 Gas connections  
Connecting gas supply piping  
Figure 7-3 Gas Supply Piping - Models 601 - 801  
1. Remove the top access panel and refer to FIG.’s 7-1 thru  
7-3 to pipe gas to the boiler.  
a. Install ground joint union for servicing, when  
required.  
b. Install a manual shutoff valve in the gas supply  
piping outside boiler jacket when required by local  
codes or utility requirements.  
MANUAL  
SHUTOFF VALVE  
(FACTORY SUPPLIED)  
c. In Canada – When using manual main shutoff  
valves, it must be identified by the installer.  
GAS SUPPLY  
2. Install sediment trap / drip leg.  
Figure 7-1 Gas Supply Piping - Model 400  
SEDIMENT TRAP/  
DRIP LEG  
UNION  
(FIELD SUPPLIED)  
UNION  
(FIELD SUPPLIED)  
GAS SUPPLY  
3. Support piping with hangers, not by the boiler or its  
accessories.  
The gas valve and blower will not support  
the weight of the piping. Do not attempt  
ƽ WARNING  
SEDIMENT TRAP/  
DRIP LEG  
to support the weight of the piping with  
the boiler or its accessories. Failure to  
comply could result in severe personal  
injury, death, or substantial property  
damage.  
MANUAL  
SHUTOFF VALVE  
(FACTORY SUPPLIED)  
4. Purge all air from the gas supply piping.  
5. Before placing the boiler in operation, check the boiler  
and its gas connection for leaks.  
a. The appliance must be disconnected from the gas  
supply piping system during any pressure testing of  
that system at a test pressure in excess of 1/2 PSIG  
(3.5 kPa).  
Figure 7-2 Gas Supply Piping - Model 501  
UNION  
(FACTORY INSTALLED)  
b. The appliance must be isolated from the gas supply  
piping system by closing a manual shutoff valve  
during any pressure testing of the gas supply piping  
system at test pressures equal to or less than 1/2 PSIG  
(3.5 kPa).  
MANUAL  
SHUTOFF VALVE  
(FACTORY SUPPLIED)  
c. The appliance and its gas connection must be leak  
tested before placing it in operation.  
GAS SUPPLY  
Do not check for gas leaks with an open  
ƽ WARNING  
flame – use the bubble test. Failure to  
SEDIMENT TRAP/  
DRIP LEG  
use the bubble test or check for gas leaks  
can cause severe personal injury, death, or  
substantial property damage.  
6. Use pipe sealing compound compatible with propane  
gases. Apply sparingly only to male threads of the pipe  
joints so that pipe dope does not block gas flow.  
46  
Installation & Operation Manual  
7 Gas connections  
(continued)  
Failure to apply pipe sealing compound  
as detailed in this manual can result  
in severe personal injury, death, or  
substantial property damage.  
Natural gas:  
Pipe sizing for natural gas  
ƽ WARNING  
1. Refer to Table 7A for pipe length and diameter. Based on  
rated boiler input (divide by 1,000 to obtain cubic feet per  
hour).  
Use two wrenches when tightening gas  
piping at boiler (FIG. 7-4), using one  
wrench to prevent the boiler gas line  
connection from turning. Failure to  
support the boiler gas connection pipe  
to prevent it from turning could damage  
gas line components.  
ƽ WARNING  
a. Table 7A is only for natural gas with specific gravity  
0.60 inches, with a pressure drop through the gas  
piping of 0.5 inches w.c.  
b. For additional gas pipe sizing information, refer to  
ANSI Z223.1 (or B149.1 for Canadian installations).  
Figure 7-4 Inlet Pipe with Backup Wrench  
Natural gas supply pressure requirements  
USE BACKUP WRENCH TO  
PREVENT PIPE FROM ROTATING  
1. Pressure required at the gas valve inlet pressure port:  
• Maximum 14 inches w.c. (3.5 kPa) with no flow  
(lockup) or with boiler on.  
• Minimum 4 inches w.c. (.99 kPa) with gas flowing (verify  
during boiler startup).  
2. Install 100% lockup gas pressure regulator in supply line  
if inlet pressure can exceed 14 inches w.c. (3.5 kPa) at any  
time. Adjust lockup regulator for 14 inches w.c. (3.5 kPa)  
maximum.  
Propane Gas:  
Knight XL boilers are typically shipped  
ready to fire on natural gas. Check boiler  
ƽ WARNING  
rating plate to determine which fuel the  
boiler is set for. If set to natural gas, it may  
be converted to LP by installing an orifice  
or by making a gas valve adjustment (see  
pages 13 and 14). In order to operate on LP  
gas, an orifice MUST BE installed or a gas  
valve adjustment MUST BE made. Failure  
to comply could result in severe personal  
injury, death, or substantial property  
damage.  
Maximum inlet gas pressure must not  
NOTICE  
exceed the value specified. Minimum  
value listed is for the purposes of input  
adjustment.  
Pipe sizing for propane gas  
1. Contact gas supplier to size pipes, tanks, and 100% lockup  
gas pressure regulator.  
Propane Supply Pressure Requirements  
1. Adjust propane supply regulator provided by the gas  
supplier for 14 inches w.c. (3.2 kPa) maximum pressure.  
2. Pressure required at gas valve inlet pressure port:  
• Maximum 14 inches w.c. (3.2 kPa) with no flow (lockup)  
or with boiler on.  
• Minimum 8 inches w.c. (1.9 kPa) with gas flowing (verify  
during boiler startup).  
Ensure that the high gas pressure regulator  
ƽ WARNING  
is at least 10 feet (3 m) upstream of the  
appliance.  
47  
Installation & Operation Manual  
7 Gas connections  
Table 7A Natural Gas Pipe Size Chart  
Maximum  
Nominal  
Iron Pipe  
Size  
Natural Gas Pipe Capacity Chart  
Length of Pipe in Straight Feet  
Capacity of Pipe  
in Thousands of  
Btu/hr per hour  
for gas pressures  
of 14 Inches  
Water Column  
(0.5 PSIG) or less  
and a pressure  
drop of 0.5 Inch  
Water Column  
(Based on NAT  
GAS, 1025 Btu/  
hr per Cubic Foot  
of Gas and 0.60  
Specific Gravity)  
(inches)  
10  
20  
30  
40  
50  
60  
70  
80  
90 100 125 150 175 200  
175  
369  
697  
120  
256  
477  
97  
82  
N/A  
155  
292  
595  
N/A N/A N/A N/A N/A N/A N/A N/A N/A  
1/2  
3/4  
1
205  
384  
789  
174  
328  
677  
141 128 121 113 106  
95  
86  
79  
74  
267 246 236 210 200 179 164 149 138  
543 502 472 441 410 369 333 308 287  
830 769 707 666 636 564 513 472 441  
1400 974  
1-1/4  
1-1/2  
2
2150 1500 1210 1020 923  
4100 2820 2260 1950 1720 1560 1440 1330 1250 1180 1100 974 871 820  
6460 4460 3610 3100 2720 2460 2310 2100 2000 1900 1700 1540 1400 1300  
11200 7900 6400 5400 4870 4410 4000 3800 3540 3330 3000 2720 2500 2340  
23500 16100 13100 11100 10000 9000 8300 7690 7380 6870 6150 5640 5130 4720  
2-1/2  
3
4
Check inlet gas supply  
CSA or UL listed flexible gas connections  
4. Slowly turn on the gas supply at the field installed  
manual gas valve.  
NOTICE  
are acceptable, but you must exercise  
caution to ensure that the line has adequate  
capacity to allow your boiler to fire at full  
rate. Consult with local codes for proper  
installation or service procedures.  
5. Turn the power switch to the “ON” position.  
6. Adjust the temperature set point on the control panel of  
the SMART SYSTEM control module to call for heat.  
7. Observe the gas supply pressure as the burner fires at  
100% of rated input. Percent of burner input will be  
displayed on the control panel.  
DO NOT adjust or attempt to measure gas  
valve outlet pressure. Attempting to alter  
or measure the gas valve outlet pressure  
could result in damage to the valve, causing  
potential severe personal injury, death, or  
substantial property damage.  
ƽ WARNING  
8. Ensure inlet pressure is within specified range.  
Minimum and maximum gas supply pressures are  
specified in this section of the manual.  
9. If gas supply pressure is within normal range and no  
adjustments are needed, proceed on to Step 11.  
The gas piping must be sized for the proper flow and length of  
pipe, to avoid excessive pressure drop. Both the gas meter and  
the gas regulator must be properly sized for the total gas load.  
10. If the gas pressure is out of range, contact the gas utility,  
gas supplier, qualified installer or service agency to  
determine the necessary steps to provide proper gas  
pressure to the control.  
If you experience a pressure drop greater than 1 inch w.c.  
(249 Pa), the meter, regulator, or gas line is undersized or in  
need of service. Perform the steps below when checking inlet  
gas supply:  
11. Turn the power switch to the “OFF” position.  
1. Turn the main power switch to the “OFF” position.  
12. Shut off the gas supply at the manual gas valve in the gas  
piping to the appliance.  
2. Shut off gas supply at the manual gas valve in the gas  
piping to the appliance.  
13. Remove the manometer from the pressure tap on top of  
the gas valve. On Models 400 - 501 re-tighten the set  
screw inside the pressure tap. On Models 601 - 801  
remove the 1/8" (3 mm) field supplied fitting and  
reinstall the pipe plug removed in Step 3.  
3. On Models 400 - 501 loosen the set screw one (1) full turn  
from inside the pressure tap on top of the gas valve. On  
Models 601 - 801 remove the 1/8" (3 mm) pipe plug on the  
inlet flange to the valve and install a suitable 1/8" (3 mm)  
fitting (field supplied) for the manometer tubing. Place  
the tubing of the manometer over the tap once the set  
screw is loosened or the 1/8" (3 mm) fitting is installed  
(depending on model) as shown in FIG.’s 7-5 thru 7-7 on  
page 49.  
48  
Installation & Operation Manual  
7 Gas connections  
(continued)  
When re-tightening the set screw, be sure  
to tighten securely to prevent gas leaks.  
Figure 7-7 Inlet Gas Supply Check - Models 601 - 801  
ƽ WARNING  
REMOVE THE 1/8” (3 MM) PIPE PLUG ON  
THE INLET FLANGE TO THE VALVE AND  
INSTALL A SUITABLE 1/8” (3 MM) FITTING  
(FIELD SUPPLIED) FOR THE MANOMETER  
TUBING.  
Do not check for gas leaks with an open  
flame -- use the bubble test. Failure to  
use the bubble test or check for gas leaks  
can cause severe personal injury, death, or  
substantial property damage.  
14. Turn on the gas supply at the manual gas valve.  
15. Turn the power switch to the “ON” position.  
16. Adjust the temperature set point on the control panel of  
the SMART SYSTEM control module to the desired  
water temperature so the appliance will call for heat.  
17. Check burner performance by cycling the system while  
you observe burner response. The burner should ignite  
promptly. Flame pattern should be stable. Turn system  
off and allow burner to cool, then cycle burner again to  
ensure proper ignition and flame characteristics.  
DETAIL  
Gas Pressure  
Figure 7-5 Inlet Gas Supply Check - Model 400  
The gas pressure must remain between 4 inches w.c. (.99  
kPa) minimum and 14 inches w.c. (3.5 kPa) maximum for  
Natural gas and between 8 inches w.c. (1.9 kPa) minimum  
and 14 inches w.c. (3.2 kPa) maximum for LP gas during  
standby (static) mode and while in operating (dynamic)  
mode. If an in-line regulator is used, it must be a minimum  
of 10 feet (3 m) from the Knight XL boiler. It is very  
important that the gas line is properly purged by the gas  
supplier or utility company. Failure to properly purge the  
lines or improper line sizing, will result in ignition failure.  
LOOSEN THE SET SCREW ONE (1) FULL TURN  
AND PLACE THE MANOMETER TUBING OVER  
THE PRESSURE TAP.  
The problem is especially noticeable in NEW LP installations  
and also in empty tank situations. This can also occur when  
a utility company shuts off service to an area to provide  
maintenance to their lines.  
Figure 7-6 Inlet Gas Supply Check - Model 501  
Gas valve replacement  
LOOSEN THE SET SCREW ONE (1) FULL TURN  
AND PLACE THE MANOMETER TUBING OVER  
THE PRESSURE TAP.  
The gas valve MUST NOT be replaced with a conventional  
gas valve under any circumstances. As an additional safety  
feature, this gas valve has a flanged connection to the venturi  
and blower.  
Failure to follow all precautions could  
result in fire, explosion, or death!  
ƽ WARNING  
DO NOT adjust or attempt to measure  
ƽ WARNING  
gas valve outlet pressure. Attempting  
to alter or measure the gas valve outlet  
pressure could result in damage to the  
valve, causing potential severe personal  
injury, death, or substantial property  
damage.  
DETAIL  
49  
Installation & Operation Manual  
8 Field wiring  
ELECTRICAL SHOCK HAZARD – For  
Installation must comply with:  
ƽ WARNING  
your safety, turn off electrical power  
supply before making any electrical  
connections to avoid possible electric  
shock hazard. Failure to do so can cause  
severe personal injury or death.  
1. National Electrical Code and any other national, state,  
provincial, or local codes, or regulations.  
2. In Canada, CSA C22.1 Canadian Electrical Code Part 1, and  
any local codes.  
Wiring must be N.E.C. Class 1.  
NOTICE  
Line voltage connections  
If original wiring as supplied with boiler  
must be replaced, use only type 105°C  
wire or equivalent.  
1. Connect 120 VAC power wiring to the line voltage terminal  
strip in the junction box, as shown in FIG. 8-1.  
2. Provide and install a fused disconnect or service switch  
(15 amp recommended) as required by the code (see  
FIG. 8-1).  
Boiler must be electrically grounded as  
required by National Electrical Code  
ANSI/NFPA 70 – latest edition.  
3. When connecting a domestic hot water (DHW) pump,  
connect the wiring to the line voltage terminal strip as  
shown in FIG. 8-1.  
Label all wires prior to disconnection  
when servicing controls. Wiring errors  
can cause improper and dangerous  
operation.  
ƽ CAUTION  
4. To activate a system pump, wire as shown in FIG. 8-1. Dry  
contacts are sized for 1.5 hp/120V, 3 hp/240V or 30 amps.  
Low voltage connections  
Figure 8-1 Line Voltage Field Wiring Connections  
1. Route all low voltage wires through the knockouts in the  
rear of the boiler, as shown in FIG. 8-2.  
120V SUPPLY  
NEUTRAL  
W
2. Connect low voltage wiring to the low voltage connection  
board as shown in FIG. 8-3 on page 53 of this manual and  
the boiler wiring diagram.  
GROUND  
G
LINE  
BK  
SERVICE  
SWITCH  
Figure 8-2 Routing Field Wiring  
BK  
SYSTEM  
PUMP  
G
W
LOW VOLTAGE  
CONNECTION BOARD  
LINE VOLTAGE  
JUNCTION BOX  
BK  
G
W
BOILER  
PUMP  
LOW VOLTAGE  
WIRING KNOCKOUTS  
LINE VOLTAGE  
WIRING KNOCKOUTS  
BK  
G
W
DOMESTIC  
HOT WATER  
PUMP  
L2/N  
G
L1  
50  
Installation & Operation Manual  
8 Field wiring  
(continued)  
If TST20015 is not compatible with the indirect tank, a  
tank thermostat can be used to control the boiler. The  
tank thermostat should be installed per the manufacturer’s  
instructions and wired to the DHW Thermostat terminals on  
the low voltage connection board (FIG. 8-3).  
Thermostat  
1. Connect the room thermostats or end switches (isolated  
contact only) to room thermostat 1, 2, or 3, as shown in  
FIG. 8-3.  
2. Install the thermostat on the inside wall away from  
influences of drafts, hot or cold water pipes, lighting  
fixtures, television, sunlight, or fireplaces.  
Louver proving switch  
1. When the operation of the louvers needs to be verified  
before the boiler fires, remove the jumper wire from these  
terminals and connect them to the normally open contacts  
on its proving switch (FIG. 8-3).  
3. Thermostat anticipator (if applicable):  
a. If connected directly to boiler, set for 0.1 amps.  
b. If connected to relays or other devices, set to match  
total electrical power requirements of connected  
devices. See device manufacturers’ specifications  
and thermostat instructions for details.  
High gas pressure switch  
1. If a switch is provided to detect excessive gas pressure,  
remove the jumper wire from the terminals on the  
connection board, and then connect them to its normally  
closed contacts (FIG. 8-3).  
Outdoor temperature sensor  
1. Mount the sensor on an exterior wall, shielded from  
direct sunlight or flow of heat or cooling from other  
sources.  
Low gas pressure switch  
1. If a switch is provided to detect low gas pressure, remove  
the jumper wire from the terminals on the connection  
board and connect them to its normally open contacts  
(FIG. 8-3).  
2. Route sensor wires through a knockout at the rear of the  
boiler (see FIG. 8-2).  
3. Connect the outdoor temperature sensor (FIG. 8-3) to  
the outdoor sensor terminals on the connection board to  
enable outdoor reset operation of the Knight XL. Do not  
install the outdoor sensor.  
2. If both a high and low gas pressure switch is used, connect  
their respective contacts in series, and connect them to the  
terminals on the connection board (FIG. 8-3).  
Variable speed system pump  
DHW  
(Domestic  
Hot  
Water)  
If a variable speed pump is used in the primary loop, and  
a 0-10V signal is available from the pump speed control,  
this signal can be used by the SMART SYSTEM control to  
anticipate changes in the building heat load. By connecting this  
0 - 10V signal to the 0 - 10V SYS PUMP IN terminals, the boiler  
(or cascade) can modulate up and down as the primary flow  
increases and decreases.  
thermostat  
Connect storage indirect water heater (DHW) thermostat  
(FIG. 8-3) to the DHW thermostat terminals on the  
connection board. If a tank sensor is connected (see DHW  
Tank Sensor below) the tank thermostat is ignored.  
DHW tank sensor  
Boiler pump speed output  
By installing a tank sensor, the SMART SYSTEM control can  
perform the tank thermostat function. The SMART SYSTEM  
control automatically detects the presence of this sensor, and  
generates a DHW call for heat when the tank temperature  
drops 6°F (3°C) below the tank set point, and finishes the call  
for heat when the tank temperature reaches the tank set point.  
The tank sensor included with the Lochinvar Squire® indirect  
DHW tanks (TST20015) is the only sensor suitable for use  
with the SMART SYSTEM control. Connect the sensor  
leads to the Tank Sensor terminals on the low voltage  
connection board (FIG. 8-3). Consult the tank manufacturer  
for application and performance when used with any other  
indirect tank.  
This 0 - 10V output is available to control the speed of a variable  
speed boiler pump. The SMART SYSTEM control will vary the  
speed of this pump in order to maintain a minimum T across  
the heat exchanger, as well as prevent high limit lockouts when  
the flow in the primary loop is extremely low. Connect this  
output to the 0 - 10V input on the boiler pump speed control.  
Rate output  
This output provides a 0 - 10V signal that is proportional to the  
firing rate of the boiler. This may be used by a BMS system to  
monitor the actual rate of the boiler.  
Failure to use the correct sensor may  
ƽ WARNING  
result in the tank temperature being either  
above or below the set point. Failure to  
consult the manufacturer of the indirect  
tank, when the Squire is not used, may  
result in decreased performance or the  
risk of scald injury.  
51  
Installation & Operation Manual  
8 Field wiring  
Modbus  
Alarm contacts  
When the optional ModBus interface module is installed, the The SMART SYSTEM control closes another set of contacts  
RS-485 ModBus cable is connected to these terminals. Use whenever the boiler is locked out or the power is turned off.  
shielded, 2-wire twisted pair cable. If desired, the shield can This can be used to turn on an alarm, or signal a Building  
be connected to ground by installing a jumper wire between  
terminals 1 and 3 on connector X5 on the optional ModBus  
interface module.  
Management System that the boiler is down.  
Wiring of the cascade  
Flow switch  
1. A flow switch is used to guarantee flow through the boiler  
before allowing it to fire. The flow switch must be installed  
at the boiler outlet.  
When wiring the boilers for Cascade operation, select one  
boiler as the Leader boiler. The remaining boilers will be  
designated as Members. See page 60 “Configuration of the  
Cascade” for a detailed explanation of this procedure.  
2. Remove the jumper wire from the terminals on the  
connection board and connect these terminals to the  
normally open contacts on the flow switch (FIG. 8-3).  
Connect the system supply sensor and outdoor air sensor (if  
used) to the Leader boiler. For the Cascade system to work  
properly the system supply sensor must be installed. The  
location of the system supply sensor should be downstream  
of the boiler connections in the main system loop (FIG.’s 6-7  
through 6-11). The system supply sensor should be wired to  
the Low Voltage Connection Board at the terminals marked  
for the system sensor (see FIG. 8-3). The Leader control will  
use the water temperature at the system supply sensor to  
control the operation of the Cascade.  
System supply sensor  
1. By installing the system supply sensor into the supply of  
the primary loop, the temperature of the system supply can  
be controlled. The SMART SYSTEM control automatically  
detects the presence of this sensor, and controls the boiler  
firing rate to maintain the system supply temperature to the  
set point (if the outlet sensor control is currently selected).  
See the Knight XL Service Manual for instructions on how  
to use the inlet sensor as the controlling sensor. When the  
inlet sensor is programmed as the controlling sensor, it is  
vital that the SYSTEM SUPPLY sensor be installed. DO  
NOT INSTALL THE SYSTEM SUPPLY SENSOR INTO  
THE SYSTEM RETURN.  
If outdoor air reset is desired, the outdoor air sensor should be  
wired to the Low Voltage Connection Board at the terminals  
marked for the outdoor air sensor (FIG. 8-3). If the outdoor  
air sensor is connected, the Leader control will calculate the  
water temperature set point based on the programmed reset  
curve parameters. If the outdoor air sensor is not connected,  
the Leader control will maintain the fixed water temperature  
set point that is programmed into the control.  
2. The TST2032 sensor provided with the boiler must be used  
for the system sensor.  
If a Thermostat or Zone Control enable output is available,  
it should be wired to the Low Voltage Connection Board  
on the Leader boiler at the terminals marked for one of the  
Room Thermostats 1-3 (FIG. 8-3). If the boilers are to run  
continuously, connect a jumper wire between the R and W  
terminals for the Thermostat input. This will initiate a call for  
heat on the Cascade.  
3. Connect these terminals to the system supply sensor  
(FIG. 8-3).  
Boiler management system  
1. An external control may be connected to control either  
the firing rate or the set point of the boiler. If the  
external control uses a set of contacts to enable the boiler,  
connect the contacts to the Room Thermostat 1 terminals.  
Otherwise, the SMART SYSTEM control will be enabled by  
the 0-10V signal.  
Communication between the Leader boiler and the Member  
boilers is accomplished by using shielded, 2-wire twisted pair  
communication cable. Connect one of the twisted pair wires  
to Cascade terminal A on each of the Low Voltage Connection  
boards, and the other wire of the twisted pair to Cascade  
terminal B on each of the Low Voltage Connection Boards.  
Connect the shield wires to one of the shield terminals on  
the Low Voltage Connection Boards (FIG. 8-3). If more than  
two boilers are on the Cascade, daisy chain the wiring from  
the Cascade terminals on the second boiler to the Cascade  
terminals on the third boiler, then from the third to the forth,  
and so on. The connections between boilers can be made in  
any order, regardless of the addresses of the boilers. Try to  
keep each cable as short as possible.  
2. Make sure the ground terminal is connected to the ground  
output terminal of the external control, and the 0 - 10 VDC  
terminal is connected to the 0 - 10 VDC terminal of the  
external control.  
Runtime contacts  
The SMART SYSTEM control closes a set of dry contacts  
whenever the burner is running. This is typically used by  
Building Management Systems to verify that the boiler is  
responding to a call for heat.  
52  
Installation & Operation Manual  
8 Field wiring  
(continued)  
Figure 8-3 Low Voltage Field Wiring Connections  
53  
Installation & Operation Manual  
9 Condensate disposal  
Use materials approved by the authority  
having jurisdiction. In the absence of other  
authority, PVC and CPVC pipe must comply  
with ASTM D1785 or D2845. Cement and  
primer must comply with ASME D2564 or  
F493. For Canada use CSA or ULC certified  
PVC or CPVC pipe, fittings, and cement.  
Condensate drain  
NOTICE  
NOTICE  
1. This boiler is a high efficiency appliance that produces  
condensate.  
2. The side of the boiler has a 1/2 inch (12.7 mm) PVC  
union for connection of a 1/2 inch (12.7 mm) PVC pipe  
(FIG. 9-1).  
To allow for proper drainage on large  
horizontal runs, a second line vent may  
be required and tubing size may need to  
increase to 1 inch (25 mm).  
3. Slope condensate tubing down and away from the boiler  
into a drain or condensate neutralizing filter. Condensate  
from the Knight XL will be slightly acidic (typically with  
a pH from 3 to 5). Install a neutralizing filter if required  
by local codes.  
The condensate line must remain  
unbstructed, allowingfreeowofcondensate.  
If condensate is allowed to freeze in the line  
or if the line is obstructed in any other  
manner, condensate can exit from the boiler  
tee, resulting in potential water damage to  
property.  
A Neutralizer Kit (FIG. 9-1) is available from the factory  
(KIT3087 for Models 400 - 501 and KIT3046 for Models  
601 - 801).  
4. Install the 1/2 inch (12.7 mm) PVC tee assembly (shipped  
with the unit) as shown in FIG. 9-1.  
8. A condensate removal pump is required if the boiler is  
below the drain. When installing a condensate pump, select  
one approved for use with condensing boilers and furnaces.  
The pump should have an overflow switch to prevent  
property damage from condensate spillage. The switch  
should be wired in series with the blocked drain switch  
inside the boiler (see FIG. 10-1 on page 56).  
5. Leave the top of the 1/2 inch (12.7 mm) tee OPEN. This  
is needed as a vacuum break.  
6. Do not expose condensate line to freezing temperatures.  
7. Use only plastic tubing or piping as a condensate drain  
line (FIG. 9-1).  
Figure 9-1 Condensate Disposal  
1/2" PVC TEE ASSEMBLY  
(FACTORY SUPPLIED)  
1/2" PVC UNION  
(FACTORY SUPPLIED)  
NEUTRALIZER KIT  
FLOOR DRAIN OR  
DRAIN PAN  
KIT3087 shown for illustration purposes.  
54  
Installation & Operation Manual  
10 Start-up  
3. Fill to correct system pressure. Correct pressure will vary  
with each application.  
Check/control water chemistry  
Do not use petroleum-based cleaning or  
ƽ CAUTION  
a. The minimum cold water fill pressure for a  
commercial system is 12 psi (82.7 kPa).  
sealing compounds in the boiler system.  
Damage to elastomer seals and gaskets  
in the system could occur, resulting in  
substantial property damage.  
b. Pressure will rise when boiler is turned on and  
system water temperature increases.  
Hardness less than 7 grains  
4. At initial fill and during boiler startup and testing, check  
system thoroughly for any leaks. Repair all leaks before  
proceeding further.  
1. Consult local water treatment companies for hard water  
areas (above 7 grains hardness).  
Eliminate all system leaks. Continual  
Chlorine concentration less than 200 ppm  
ƽ WARNING  
fresh makeup water will reduce boiler life.  
Minerals can build up in the heat exchanger,  
reducing heat transfer, overheating the heat  
exchanger, and causing heat exchanger  
failure.  
1. Do not fill boiler or operate with water containing  
chlorine in excess of 200 ppm.  
2. Filling with chlorinated fresh water should be acceptable  
since drinking water chlorine levels are much lower.  
Purge air from water system  
3. Do not use the boiler to directly heat swimming pool or  
spa water.  
1. Purge air from system:  
a. Connect a hose to the purge valve (see purge/drain  
valves, in piping diagrams on page 46). Route the  
hose to an area where water can drain and be seen.  
b. Close the boiler or system isolation valve between  
the purge valve and fill connection to the system.  
c. Close zone isolation valves.  
Test/replace freeze protection uid  
1. For systems using freeze protection fluids, follow fluid  
manufacturer’s instructions.  
2. Freeze protection fluid must be replaced periodically due  
to degradation of inhibitors over time. Follow all fluid  
manufacturer’s instructions.  
d. Open quick-fill valve on cold water makeup line.  
e. Open purge valve.  
f. One zone at a time, open the isolation valves. Allow  
water to run through the zone, pushing out the air.  
Run until no noticeable air flow is present. Close the  
zone isolation valves and proceed with the next zone.  
Follow this procedure until all zones are purged.  
g. Close the quick-fill water valve and purge valve and  
remove the hose. Open all isolation valves. Watch  
that system pressure rises to correct cold-fill  
pressure.  
Freeze protection (when used)  
1. Determine freeze protection fluid quantity using  
system water content, following fluid manufacturer’s  
instructions. Boiler water content is listed on page 7.  
Remember to include expansion tank water content.  
2. Local codes may require a backflow preventer or actual  
disconnect from city water supply.  
h. After the system has operated for a while, eliminate  
any residual air by using the manual air vents located  
throughout the system.  
i. If purge valves are not installed in the system, open  
the manual air vents in the system one at a time,  
beginning with the lowest floor. Close the vent when  
water squirts out. Repeat with remaining vents.  
3. When using freeze protection fluid with automatic fill,  
install a water meter to monitor water makeup. Freeze  
protection fluid may leak before the water begins to  
leak, causing concentration to drop, reducing the freeze  
protection level.  
4. The freeze protection set points may be lowered when  
freeze protection fluid is used (see the Knight XL Service  
Manual).  
2. Open automatic air vent (diaphragm-type or bladder-  
type expansion tank systems only) one turn.  
Fill and test water system  
3. Open other vents:  
a. Starting on the lowest floor, open air vents one at a  
time until water squirts out.  
b. Repeat with remaining vents.  
1. Fill system only after ensuring the water meets the  
requirements of this manual.  
2. Close manual and automatic air vents and boiler drain  
valve.  
4. Refill to correct pressure.  
55  
Installation & Operation Manual  
10 Start-up  
Propane boilers only – Your propane  
suppliermixesanodorantwiththepropane  
to make its presence detectable. In some  
instances, the odorant can fade, and the  
gas may no longer have an odor. Before  
startup (and periodically thereafter), have  
the propane supplier verify the correct  
odorant level in the gas.  
Check for gas leaks  
ƽ WARNING  
Before starting the boiler, and during  
ƽ WARNING  
initial operation, smell near the floor and  
around the boiler for gas odorant or any  
unusual odor. Remove the top access  
panel and smell the interior of the boiler  
enclosure. Do not proceed with startup  
if there is any indication of a gas leak.  
Use an approved leak detection solution.  
Repair any leaks at once.  
Check thermostat circuit(s)  
1. Disconnect the two external wires connected to each of  
the room thermostat terminals on the connection board.  
DO NOT adjust or attempt to measure  
gas valve outlet pressure. The gas valve is  
factory set for the correct outlet pressure.  
This setting is suitable for natural gas and  
propane, requiring no field adjustment.  
Attempting to alter or measure the gas  
valve outlet pressure could result in  
damage to the valve, causing potential  
severe personal injury, death, or  
substantial property damage.  
ƽ WARNING  
2. Connect a voltmeter across these two incoming wires.  
Close each thermostat, zone valve, and relay in the  
external circuit one at a time and check the voltmeter  
reading across the incoming wires.  
3. There should NEVER be a voltage reading.  
4. If a voltage does occur under any condition, check and  
correct the external wiring. (This is a common problem  
when using 3-wire zone valves.)  
Figure 10-1 Condensate Trap  
5. Once the external thermostat circuit wiring is checked and  
corrected if necessary, reconnect the external thermostat  
circuit wires to the connection board. Allow the boiler to  
cycle.  
RETAINING  
SCREW  
2” PVC CAP WITH  
BLOCKED DRAIN SWITCH  
Inspect/ll condensate system  
PVC TEE ASSEMBLY  
(FACTORY SUPPLIED)  
Inspect/check condensate lines and ttings  
1. Inspect the condensate drain line, condensate PVC  
fittings and condensate trap.  
Fill condensate trap with water  
1. Remove the PVC cap retaining screw from the PVC cap  
(FIG. 10-1).  
CONDENSATE FROM  
HEAT EXCHANGER  
TO FLOOR  
DRAIN  
2. Remove the 2 inch PVC cap with the switch located at the  
top of the trap (FIG. 10-1).  
3. Fill with fresh water until the water begins to pour out of  
the drain.  
4. Replace the cap. Press the cap onto the trap until the cap  
makes contact with the drain.  
5. Replace the retaining screw.  
The condensate trap (FIG. 10-1) must be  
filled with water during all times of boiler  
ƽ WARNING  
operation to avoid flue gas emission from  
the condensate drain line. Failure to fill  
the trap could result in severe personal  
injury or death.  
56  
Installation & Operation Manual  
10 Start-up  
(continued)  
Final checks before starting the boiler  
Check vent piping and air piping  
1. Check for gastight seal at every connection, seam of air  
piping, and vent piping.  
Read the Knight XL Service Manual to familiarize yourself  
with SMART SYSTEM control module operation. Read  
this manual, page 58 for proper steps to start boiler.  
Venting system must be sealed gastight  
ƽ WARNING  
to prevent flue gas spillage and carbon  
monoxide emissions, which will result in  
severe personal injury or death.  
Verify the boiler and system are full of water and all  
system components are correctly set for operation.  
Check gas piping  
Verify the preparation procedures of Section 10, pages 55  
and 56 have been completed.  
1. Check around the boiler for gas odor following the  
procedure on page 46 of this manual (connecting gas  
supply piping).  
Fill the vent condensate trap with water (removing the  
retaining screw in order to remove the 2 inch PVC cap  
with the switch located at the top of the trap). Replace  
the cap. Press the cap onto the trap until the cap makes  
contact with the drain. Replace the retaining screw.  
If you discover evidence of any gas leak,  
ƽ WARNING  
shut down the boiler at once. Find the  
leak source with a bubble test and repair  
immediately. Do not start the boiler again  
until corrected. Failure to comply could  
result in severe personal injury, death, or  
substantial property damage.  
Verify electrical connections are correct and securely  
attached.  
Propane boilers – verify conversion  
Inspectventpipingandairpipingforsignsofdeterioration  
from corrosion, physical damage or sagging. Verify air  
piping and vent piping are intact and correctly installed  
per this manual.  
1. Verify propane conversion has been completed per the  
Propane Conversion instructions.  
DO NOT adjust or attempt to measure  
ƽ WARNING  
gas valve outlet pressure. The gas valve is  
Start the boiler  
factory-set for the correct outlet pressure.  
This setting is suitable for natural gas and  
propane, requiring no field adjustment.  
Attempting to alter or measure the gas  
valve outlet pressure could result in  
damage to the valve, causing potential  
severe personal injury, death, or  
substantial property damage.  
1. Read and follow the Operating instructions in FIG. 10-2,  
page 58.  
If boiler does not start correctly  
1. Check for loose connections, blown fuse or service switch  
off?  
Knight XL boilers are typically shipped  
2. Is boiler water temperature above 200°F (93°C)?  
3. Is thermostat set below room temperature?  
4. Is gas turned on at meter or boiler?  
ƽ WARNING  
ready to fire on natural gas. Check boiler  
rating plate to determine which fuel the  
boiler is set for. If set to natural gas, it may  
be converted to LP by installing an orifice  
or by making a gas valve adjustment (see  
pages 13 and 14). In order to operate on  
LP gas, an orifice MUST BE installed or  
a gas valve adjustment MUST BE made.  
Failure to comply could result in severe  
personal injury, death, or substantial  
property damage.  
5. Is incoming gas pressure less than 4 inches w.c. (.99 kPa)?  
If none of the above corrects the problem, refer to the  
Troubleshooting Section of the Knight XL Service Manual.  
Check system and boiler  
Check ame and combustion  
Check water piping  
1. Turn the main power off to the boiler by placing the  
“On/Off” switch in the OFF position.  
1. Check system piping for leaks. If found, shut down  
the boiler and repair immediately. (See WARNINGS  
on pages 55 and 56 (startup) regarding failure to repair  
leaks.)  
2. Remove the flue temperature sensor from the flue pipe  
connection. NOTE: Combustion measurements will be  
made at this point.  
2. Vent any remaining air from the system using manual  
vents. Air in the system will interfere with circulation  
and cause heat distribution problems and noise.  
3. Turn the main power on to the boiler by placing the  
“On/Off” switch in the ON position.  
57  
Installation & Operation Manual  
10 Start-up  
Figure 10-2 Operating Instructions  
FOR YOUR SAFETY READ BEFORE OPERATING  
WARNING: If you do not follow these instructions exactly, a fire or explosion  
may result causing property damage, personal injury, or loss of life.  
• Immediately call your gas supplier from a  
A. This appliance does not have a pilot. It is  
neighbor’s phone. Follow the gas supplier’s  
instructions.  
equipped with an ignition device which  
automatically lights the burner. Do not try  
• If you cannot reach your gas supplier, call  
the fire department.  
to light the burner by hand.  
B. BEFORE OPERATING smell all around  
the appliance area for gas. Be sure to  
smell next to the floor because some gas  
is heavier than air and will settle on the  
floor.  
C. Use only your hand to turn the gas control knob.  
Never use tools. If the handle will not turn by  
hand, don’t try to repair it, call a qualified service  
technician. Force or attempted repair may result  
in a fire or explosion.  
WHAT TO DO IF YOU SMELL GAS  
D. Do not use this appliance if any part has been  
under water. Immediately call a qualified  
• Do not try to light any appliance.  
service technician to inspect the appliance and  
to replace any part of the control system and  
any gas control which has been under water.  
• Do not touch any electric switch; do  
not use any phone in your building.  
OPERATING INSTRUCTIONS  
1. STOP! Read the safety information  
above on this label.  
8. Turn gas shutoff valve clockwise to “ON”.  
Handle will be parallel to pipe.  
2. Set the thermostat to lowest setting.  
9. Install top cover.  
10. Turn on all electric power to appliance.  
11. Set thermostat to desired setting.  
3. Turn off all electric power to the  
appliance.  
4. This appliance is equipped with an  
ignition device which automatically lights  
the burner. Do not try to light the burner  
by hand.  
12. If the appliance will not operate, follow the  
instructions “To Turn Off Gas To Appliance” and  
call your service technician or gas supplier.  
5. Remove top cover.  
6. Turn gas shutoff valve counterclockwise  
to “OFF”. Handle will be perpendicular to  
pipe. Do not force.  
7. Wait five (5) minutes to clear out any gas.  
If you then smell gas, STOP! Follow “B”  
in the safety information above on this label.  
If you don’t smell gas, go to next step.  
TO TURN OFF GAS TO APPLIANCE  
1. Set the thermostat to lowest setting.  
4. Turn gas shut off valve counterclockwise to  
“OFF”. Handle will be perpendicular to pipe.  
Do not force.  
2. Turn off all electric power to the appliance  
if service is to be performed.  
5. Install top cover.  
3. Remove top cover.  
LBL2284 REV -  
58  
Installation & Operation Manual  
10 Start-up  
(continued)  
Check ame and combustion (continued)  
Set space heating operation  
4. Place the boiler into the active position by pressing the  
RIGHT SELECT [ON] key (FIG. 11-1, page 67).  
Determine controlling sensor  
For space heating systems, the temperature control can be  
based on one of three sensors; the inlet, outlet, or system  
supply sensor. The SMART SYSTEM control is programmed  
at the factory to control the temperature of the outlet  
sensor. The control will automatically switch to the system  
supply sensor once it is connected. If it is desired to base  
the temperature control on the inlet sensor, the appropriate  
parameter must be changed in the control. See the Knight XL  
Service Manual for a detailed explanation of this procedure.  
5. Locate the pinhole button below the RESET button on  
the display board (FIG. 11-1). Insert a thin wire (such  
as a paper clip) into the hole and press the button once  
and hold for 5 seconds to place the boiler into Service  
Mode. In Service Mode the boiler will fire at ignition  
speed and will then modulate up to full fire.  
6. Insert the probe from a combustion analyzer into the  
hole left by the removal of the flue temperature sensor.  
Verify space heat circulator mode  
7. Once the boiler has modulated up to full fire, measure  
the combustion. The values should be in the range  
listed in Table 10A below. The CO levels should be less  
than 150 ppm for a properly installed unit.  
The Space Heating Mode controls both the system (primary)  
pump (if connected), and the boiler (secondary) pump.  
When the SMART SYSTEM control receives a space heating  
call for heat, it turns on the system pump. If the boiler is not  
heating an indirect DHW (Domestic Hot Water) tank, and  
the set point is not met, it also turns on the boiler pump.  
After the space heating call for heat ends, the system pump  
continues to run for a short period of time. The system  
pump can be programmed to run continuously, except  
during outdoor shutdown. If the boiler pump was running,  
it continues to run for a short period of time as well. These  
pump delays are factory set to 30 seconds. If different delays  
are desired, the appropriate parameters in the control must  
be changed. See the Knight XL Service Manual for a detailed  
explanation of this procedure.  
If the combustion is not within the specified range,  
reference the Troubleshooting Section of the Knight  
XL Service Manual for possible causes and corrective  
actions.  
Table 10A Flue Products Chart  
Natural Gas  
CO2 O2  
Propane  
CO2  
O2  
8.0% - 10% 3.0% - 6.5% 9.0% - 11% 4.1% - 6.9%  
Adjust set point temperature  
8. Once the combustion analysis is complete, test the  
safety shutoff device by turning the manual shutoff  
valve to the OFF position and ensuring that the boiler  
shuts down and registers an alarm. Open the manual  
shutoff valve, reset the control, and return to Service  
Mode.  
Please note that the brackets ([]) denote  
screen status.  
NOTICE  
The NAVIGATION dial may be used during normal  
operation to adjust the space heating and tank set point  
temperatures.  
9. Turn the main power off to the boiler and replace the  
flue temperature sensor into the flue pipe connection.  
1. From the Status Screen press the NAVIGATION dial.  
2. Turn the NAVIGATION dial counterclockwise to select  
the appropriate set point.  
3. Press the NAVIGATION dial to adjust the temperature.  
4. Once the desired temperature is displayed, press the  
RIGHT SELECT [SAVE] key.  
10. Place the boiler back into normal operation.  
You must replace the flue gas  
ƽ WARNING  
temperature sensor to prevent flue gas  
spillage into the room. Failure to comply  
could result in severe personal injury,  
death, or substantial property damage.  
5. If necessary repeat Steps 3 and 4 to make adjustments to  
additional set points.  
6. Press the RIGHT SELECT [HOME[ key to upload the  
changes.  
7. If the RIGHT SELECT [SAVE] key is not pressed, the  
new settings will be discarded.  
59  
Installation & Operation Manual  
10 Start-up  
Set domestic hot water (DHW) operation  
Verify DHW mode  
7. Turn the NAVIGATION dial to adjust the minutes. Press  
the NAVIGATION dial.  
There are two (2) modes of operation for DHW. In Normal  
Mode, when a DHW demand begins, the control will start  
the DHW pump, turn off the boiler pump (if running), and  
modulate to bring the outlet temperature to the DHW boiler  
set point. The maximum firing rate may be limited in this  
mode if desired.  
8. Turn the NAVIGATION dial to adjust the month. Press  
the NAVIGATION dial.  
9. Turn the NAVIGATION dial to adjust the date. Press the  
NAVIGATION dial.  
In Zone Mode it is assumed that the indirect DHW tank is  
piped as a zone on the primary loop. When a DHW demand  
begins, the control will turn on the DHW pump output, and  
raise the system temperature set point to the DHW boiler set  
point (if higher). The system pump and the boiler pump will  
be turned on. In this mode, any low temperature zones (such  
as radiant heating) may need additional controls to limit the  
water temperature sent to those zones.  
10. Turn the NAVIGATION dial to adjust the year. Press the  
RIGHT SELECT [SAVE] key.  
11. Press the RIGHT SELECT [HOME] key.  
The internal clock does not adjust for  
NOTICE  
Daylight Savings Time and therefore, will  
require a manual adjustment.  
Conguration of the cascade  
Set DHW target temperature  
Please note that the brackets ([]) denote  
screen status.  
NOTICE  
When in the DHW Mode, the control will modulate to  
maintain the boiler outlet temperature or system supply  
temperature to a set point. This set point is set at the factory  
to 180°F. If a different set point is desired, the appropriate  
parameter in the control must be changed. See the Knight XL  
Service Manual for a detailed explanation of this procedure.  
When installed in a Cascade system, the individual controls must  
be programmed for cascade operation. This is accomplished by  
accessing the control parameters.  
Press the [MENU] key for at least five (5) seconds. Input the  
Installer code as described in the Knight XL Service Manual.  
Once the control parameters have been accessed, use the  
NAVIGATION DIAL to select the Control Mode parameters.  
Press the NAVIGATION DIAL to access these parameters.  
Set maximum DHW fan speed  
If the rated input of the indirect tank is less than the  
maximum output of the boiler, change the maximum DHW  
fan speed setting to limit the boiler output accordingly, see  
the Knight XL Service Manual for a detailed explanation of  
this procedure.  
Rotate the NAVIGATION dial to select the parameter “Cascade  
Address”. Press the NAVIGATION dial to access this parameter.  
Each appliance in the Cascade system must be programmed  
with its own address. The boiler designated as the Leader will  
have an address of 0. The remaining boilers in the Cascade  
will be Members and have addresses from 1 - 7. Rotate the  
NAVIGATION dial to select the appropriate address. Press  
the RIGHT SELECT [SAVE] key. If installing the boilers in an  
existing system, the new boilers should be programmed as the  
Leader and/or the higher number addresses.  
Set clock  
Please note that the brackets ([]) denote  
screen status.  
NOTICE  
The SMART SYSTEM control has a built-in clock that it  
uses for its night setback feature and for logging events. This  
clock must be set when the boiler is installed, and anytime the  
boiler has been powered off for more than 4 hours. Use the  
following procedure to set the clock:  
Press the RIGHT SELECT [HOME] key to upload the address  
into the control. Repeat this procedure for all boilers in the  
Cascade, designating the Leader control and the Member  
controls.  
1. Press and hold the LEFT SELECT [MENU] key for at  
least 5 seconds.  
2. The display changes to read [PASSWORD],  
with four (4) zeros below it.  
3. Press the RIGHT SELECT [SAVE] key.  
4. The display will then show a menu with the time and  
date and temperature unit.  
5. Press the NAVIGATION dial twice.  
6. Turn the NAVIGATION dial to adjust the hours. Press  
the NAVIGATION dial.  
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11 Operating information  
General  
How the boiler operates  
The Knight XL uses an advanced stainless steel heat exchanger  
and electronic control module that allows fully condensing  
operation. The blower pulls in air and pushes flue products  
out of the boiler through the heat exchanger and flue piping.  
The control module regulates blower speed to control the  
boiler firing rate. The gas valve senses the amount of air  
flowing into the boiler and allows only the right amount of  
gas to flow.  
DHW priority  
The SMART SYSTEM control allows the connection of a DHW  
thermostat or tank sensor to the low voltage connection board.  
When a tank sensor is connected, the DHW thermostat input  
is ignored.  
DHW / space heating (SH) cycling  
If a DHW call for heat is received while a space heating call  
is in progress and the DHW is in Normal Mode, the control  
will start the DHW pump and shut the boiler pump off. The  
system pump will remain on. If the space heating call is still  
active while the DHW call is in operation, the control will wait  
for 30 minutes (time adjustable by installer) then it will switch  
back to the space heating demand. There is a timer to switch  
from space heating to DHW and a timer to switch from DHW  
to space heating. The control will switch back and forth until  
one of the heat demands end. This function does not apply to  
cascade systems.  
How the control module operates  
The SMART SYSTEM control module receives inputs from  
boiler sensors and external devices. The control module  
activates and controls the blower and gas valve to regulate  
heat input and switches the boiler, Domestic Hot Water  
(DHW), and system pumps on and off as needed. The user  
programs the module to meet system needs by adjusting  
control parameters. These parameters set operating  
temperatures and boiler operating modes. Boiler operation  
can be based on boiler outlet water temperature, boiler inlet  
water temperature, system temperature, a 0 - 10V signal, or  
Modbus, depending on the parameter settings.  
Programmable controlling sensor  
The control module is programmed to use the outlet sensor  
as the control sensor by default. If a system supply sensor is  
connected, the control automatically uses it as the control  
sensor. The control sensor can be changed by the installer to  
the inlet sensor. If the inlet sensor is chosen as the controlling  
sensor, it is recommended that the system supply sensor be  
installed in the system supply in order to provide the best  
control of the inlet temperature.  
Control inputs and outputs  
Room thermostat  
There are three (3) thermostat connections available on this  
control. These inputs tell the boiler to provide water for space  
heating. Each thermostat connection has its own set point  
and outdoor air reset curve. When multiple thermostats have  
a call for heat the control will give priority to the demand with  
the highest set point.  
Anti-cycling  
After the burner turns off, the control will delay the next burner  
cycle for a set time period (time is adjustable by the installer).  
The time delay will be bypassed if the inlet water temperature  
drops too far during the delay.  
Example: Assume that both Room Thermostat 1 and Room  
Thermostat 2 have a call for heat. RoomThermostat 1 has  
a set point of 110°F. Room Thermostat 2 has a set point of  
140°F. The boiler will regulate the system temperature to  
140°F until Room Thermostat 2 has been satisfied. Once  
Room Thermostat 2 has been satisified the boiler will provide  
110°F water to the system.  
Boiler and system pump control  
The boiler pump will run whenever the burner is firing, unless  
the DHW is programmed for Normal Mode and the boiler is  
heating the DHW tank. The boiler pump will run during Freeze  
Protection Mode as well. It will continue to run for a short time  
after the burner turns off or the Freeze Protection Mode ends.  
When multiple temperature loops are  
ƽ CAUTION  
The system pump will run whenever there is a space heating  
call for heat, or the boiler goes into Freeze Protection Mode. It  
will continue to run for a short time after the end of the heat  
demand or the Freeze Protection Mode. The system pump can  
be programmed to run continuously if desired. In either case,  
it will not run during outdoor shutdown.  
used, thermostatic mixing valves are  
required for the protection of any low  
temperature loops.  
0 - 10V input (set point or power)  
The Knight XL can be controlled by a Building Management  
System (BMS) using a 0 - 10 VDC signal. The control can be  
configured by the installer to use this signal to either control  
set point or firing rate.  
Temperature control  
Modulation  
The Knight XL is capable of modulating its firing rate from a  
minimum of 20% to a maximum of 100%. The firing rate is  
dictated by the call for heat (i.e., space heating or domestic hot  
water), the heating load, ramp delay (if enabled), and various  
other temperature limitations.  
The Knight XL can also be programmed to accept a call for  
heat from a 0 - 10V signal, reference the Knight XL Service  
Manual for a detailed explanation of this procedure.  
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11 Operating information  
Ramp delay  
Protection features  
For systems with lower flow, the SMART SYSTEM can  
limit the firing rate (when enabled) when a space heating  
call for heat starts, or when switching from a DHW call for  
heat to a space heating call for heat. There are six (6) limits  
that can be programmed, as well as six (6) time intervals  
corresponding to each limit. The sixth limit will also limit  
the firing rate for the rest of the call for heat.  
Outlettemperature, uetemperature, andtemperature  
rise limiting  
The outlet temperature is monitored by the boiler outlet  
temperature sensor. When the outlet temperature exceeds  
185°F, the unit will reduce the fan speed. If the outlet water  
temperature exceeds 195°F (90°C) the control will shut the unit  
down until it cools off.  
Gradient limiting  
The control module monitors the flue temperature by a sensor  
located in the flue exhaust. If the flue temperature exceeds  
215°F (102°C) the control will reduce the maximum fan speed.  
If the flue temperature exceeds 240°F (115°C) the control will  
shut the unit down. The unit will restart automatically once the  
flue temperature drops 25°F (-4°C) and the minimum off time  
has expired.  
Ifduringoperationoftheboilertheoutletwatertemperature  
is rising too quickly, the control will reduce the firing rate  
to its lowest setting.  
Outdoor air reset  
If an outdoor air sensor is connected, the control module  
will calculate the set points of the three (3) space heating  
demands based on the programmed reset curves. The  
installer can change the slope of the reset curves by several  
adjustable parameters. The user can limit the maximum  
set point for the system using the space heating set points.  
The control monitors the temperature difference between  
the inlet and the outlet sensor. If this difference exceeds 55°F  
(13°C) the control will reduce the maximum fan speed. If the  
temperature difference exceeds 60°F (15°C) the control will  
shut the unit down. The unit will restart automatically once the  
temperature difference has dropped below 55°F (13°C) and the  
minimum off time has expired.  
Boost function  
If outdoor air reset is active, and any space heating  
demand has been active continuously for a set period of  
time (time adjustable by installer) and there has been no  
DHW demands, the control will increase the set point of  
that demand by a fixed number of degrees (adjustable by  
installer). This process will continue until the space heating  
demand ends, the set point reaches the programmed set  
point or a maximum of 20 increases has occurred. Once the  
system heat demand is satisfied, the set point will revert to  
the value determined by the reset curve.  
Freeze protection  
DO NOT install the boiler in a room likely to freeze.  
The following integral feature of the SMART SYSTEM control  
module provides some protection for the boiler only -- not for  
the system.  
The SMART SYSTEM control module provides  
freeze-up protection as follows when the boiler  
water temperature drops below 45°F (7°C):  
Below 45°F (7°C), the boiler and system pumps  
operate constantly.  
Night setback  
The controller may be programmed to reduce the space  
heating and DHW set points during certain times each week.  
Seven different start and stop times may be programmed  
for the space heating setback and seven start and stop times  
for the DHW setback.  
Below 37°F (3°C), the boiler turns on.  
Boiler and pumps turn off if boiler water  
temperature rises above 45°F (7°C).  
Lower temperatures may be programmed for systems  
with anti-freeze solutions.  
When system return temperatures  
Flame current support  
NOTICE  
are maintained below the dew point,  
condensation will form on the inside of the  
boiler jacket causing some internal sheet  
metal components to rust.  
To prevent nuisance shutdowns when the boiler is firing  
at minimum rates, the control will increase the firing rate  
when the flame signal drops too low.  
This feature of the SMART SYSTEM  
control module does not eliminate the  
possibility of freezing. The installation must  
still use recognized design, installation and  
maintenance practice to prevent freeze  
potential for the boiler and system.  
ƽ CAUTION  
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11 Operating information  
Connections are provided on the connection board for  
external limits such as flow switch, low water cutoff,  
gas pressure switches, and a louver proving switch. The  
SMART SYSTEM will shut off the burner and inhibit  
relighting whenever any of these external limits open.  
(continued)  
Monitor external limits  
High limit operations  
The Knight XL is equipped with adjustable automatic reset and  
manual reset high limits. The automatic reset high limit has a  
maximum set point of 200°F and the manual reset high limit  
has a maximum set point of 210°F.  
When the outlet temperature exceeds 200°F, the automatic  
high limit action occurs. The boiler shuts down until the outlet  
water temperature cools below 190°F, and a 60 second timer  
has expired. If the outlet temperature continues to increase, the  
manual reset high limit action will occur at 210°F.  
Run-time and alarm outputs  
The boiler provides dry contacts for indicating when the  
boiler is running, and when it is unable to operate.  
Run-time and cycle counting  
High limit test procedure  
The control uses two timers to monitor the total hours of  
burner operation. One timer monitors the time the boiler  
is in the Space Heating Mode. The other timer monitors  
the time the boiler is firing in the DHW Mode.  
Please note that the brackets ([]) denote  
screen status.  
NOTICE  
1. Turn ON the main power to the boiler by placing the  
ON/OFF switch in the ON position.  
The control uses two (2) ignition counters to monitor  
the amount of boiler cycles. The first counter counts all  
ignitions of the control. The second counter counts only  
ignition attempts that have failed.  
2. If boiler status reads [SHUTDOWN] place the boiler into  
the active position by pressing the RIGHT SELECT [ON]  
key.  
3. Locate the pinhole (SERVICE button) below the RESET  
button on the display board. Insert a thin wire (such as a  
paper clip) into the hole and press the button once, hold  
for five (5) seconds to place the boiler into Service Mode.  
In Service Mode the boiler will fire at ignition speed and  
will then modulate up to full fire.  
Service reminder  
The control can be programmed for service reminder  
notification. This notification will become active when  
either a set time frame has expired, or a set amount of  
running hours or cycles has expired (all adjustable by the  
installer). The display will show a Maintenance Required  
screen. The service reminder notification can be reset or  
disabled by the installer.  
4. From the Status Screen, press the NAVIGATION dial to  
access the Set Points Screen.  
5. Press the LEFT SELECT [LIMITS] key.  
The time dependent feature has been disabled by the  
manufacturer. To enable this feature change parameter K1  
to the desired time range, reference the Knight XL Service  
Manual for details regarding parameters.  
6. Select the manual reset high limit (MRHL) by pressing the  
NAVIGATION dial.  
7. Decrease the set point of the MRHL below the outlet  
temperature by turning the NAVIGATION dial  
counterclockwise.  
Error logging  
8. Press the RIGHT SELECT [SAVE] key.  
9. Press the RIGHT SELECT [HOME] key.  
The control will hold in memory the last 10 lockouts as  
well as the last 10 blockings. The date and time of the  
occurrence will be recorded as well. Only the 10 most  
current occurrences of each will be held in memory.  
10. The new parameters will upload to the control and the  
MRHL will function causing boiler shutdown and  
[LOCKOUT] to be displayed.  
Boiler temperature regulation  
11. Press the RESET button to clear the lockout.  
12. Repeat Steps 4, 5 and 6.  
Operating temperature (target)  
The SMART SYSTEM control module senses water  
temperature and regulates boiler firing and firing rate to  
achieve a target temperature. The target temperature can  
be set between 70°F (21°C) and 190°F (88°C).  
13. Set the MRHL to the appropriate set point by turning the  
NAVIGATION dial clockwise.  
14. Repeat Steps 8 and 9.  
Target temperature is fixed when the outdoor  
sensor is not installed.  
Target temperature is calculated as described  
on this page under “Outdoor Reset Operation”  
and “Target Temperature Boost” when the  
outdoor sensor is connected.  
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11 Operating information  
Low water cutoff protection  
Sequence of the cascade  
1. The SMART SYSTEM control module uses temperature  
sensing of both supply and return areas of the heat  
exchanger. If the flow rate is too low or the outlet  
temperature too high, the control module modulates and  
shuts the boiler down. This ensures boiler shutdown in  
the event of low water or low flow conditions.  
To equalize the run time of all boilers on the Cascade, the firing  
sequence will automatically be changed at set intervals.  
For the first 24 hours after initializing the Cascade, the sequence  
will be changed every hour. After that the sequence will be  
changed once every 24 hours. The switching on/off sequence  
will be as follows:  
2. Some codes and jurisdiction may accept these integral  
features of the control in lieu of requiring an additional  
limit control or low water cutoff. Consult local jurisdiction  
to determine. A low water cutoff is available from the  
factory (WTR20009).  
DAY  
Day 1  
SWITCHING ON SEQUENCE  
L-M1-M2-M3-M4-M5-M6-M7  
M1-M2-M3-M4-M5-M6-M7-L  
Day 1 + 1 hour  
Day 1 + 2 hours  
M2-M3-M4-M5-M6-M7-L-M1  
Outdoor reset operation, if used  
If a boiler is used to heat an indirect DHW tank, it will  
automatically be given the lowest priority.  
Target temperature with outdoor reset  
This feature improves the system’s efficiency as the outdoor  
temperature warms up.  
DHW, Night Setback, and Ramp Delay operation with  
cascade  
See the Knight XL Service Manual to change the settings.  
For normal mode DHW operation any boiler(s) in the Cascade  
can be selected to provide heat for a DHW call. Select a boiler to  
be designated as the DHW boiler. Connect the DHW thermostat  
or sensor to the terminals on the Low Voltage Connection  
Board marked for the corresponding device. When the boiler  
receives a DHW call, the Leader control will take that boiler  
out of the Cascade sequence. If another boiler is available, the  
Leader will start it up to take its place.  
Reset curve  
The reset curves look at outdoor air temperature and adjusts  
the set points.  
Cascade  
When multiple boilers are installed, they can be wired  
together in a cascade sequence. A maximum of eight boilers  
can be controlled from a single control. In this application  
one boiler would be designated as the Leader control and all  
others would be designated as Member controls. If installing  
the boilers in an existing system, the new boilers should  
be programmed as the Leader and/or the higher number  
addresses. The Leader control can be programmed to use  
Lead/Lag or Efficiency Optimization control methods.  
The DHW boiler will adjust its set point to the programmed  
DHW set point and will adjust its firing rate to maintain this.  
Once the DHW call has been satisfied, the Leader control will  
place that boiler back into the Cascade sequence.  
Switching of the boiler between DHW operation and SH  
operation when there is a call for both does not occur in Cascade  
Mode.  
Once the Leader boiler receives a call for heat from a room  
thermostat, BMS, or Modbus, the control will determine what  
the set point will be. If outdoor air reset is desired, connect  
the outdoor air sensor to the terminals on the Low Voltage  
Connection Board on the Leader boiler. The set point will be  
calculated based on the programmed reset curve parameters.  
See the Knight XL Service Manual to program the reset curve.  
If outdoor air reset is not desired, do not connect the outdoor  
air sensor. A fixed temperature set point can be programmed  
into the control. See page 59 of this manual to program the  
set point.  
When DHW is programmed for Zone Mode, connect the DHW  
thermostat or tank sensor to the Leader boiler. When a DHW  
call is received, the Leader will modulate the entire Cascade to  
bring the system supply temperature up to the DHW boiler set  
point (if higher).  
Night Setback operation of the boilers within the Cascade is  
available. Programming of the Night Setback will be done  
through the Leader boiler. Refer to the Knight XL Service  
manual for information regarding Night Setback.  
Ramp Delay operation of the boilers as described in the Knight  
XL Service Manual is available when the boilers are part of a  
Cascade system.  
If the water temperature at the system supply sensor is less  
than the set point + the turn-off offset - the off-on differential,  
then the control will initiate a call for heat on the Cascade  
(see the Knight XL Service Manual for an explanation of  
the offset and differential). The Leader will energize the lead  
boiler on the Cascade. For a new startup this will be the  
Leader boiler.  
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11 Operating information  
(continued)  
Sequence of operation  
OPERATION  
DISPLAY  
1. Upon a call for heat, the gas pressure switch(es) must be closed.  
2. Once the gas pressure switch(es) are closed, the control turns  
on the appropriate pumps (system and boiler pumps for space  
heating, DHW pump for DHW). The ow switch and/or LWCO  
must close.  
3. The control turns on power to the louver relay. The louver  
proving switch, air pressure switch, and blocked drain switch  
must close.  
4. The control starts a 15 second prepurge cycle by initiating the  
blower.  
5. The control starts a 4 second trial for ignition by ring the spark  
electrode and opening the gas valve.  
6. If ame is not detected within 1 second after the sparking ends,  
the control will perform a 10 second post-purge, then start  
another prepurge cycle and try to light the burner again. On  
the 501 and larger models, the control will lock out if this second  
attempt also fails. On the 400 model, the control will perform a  
total of 4 attempts before locking out.  
7. If ame is detected, it holds the ring rate steady for 5 seconds  
to let the ame stabilize, then it begins to modulate the ring rate  
based on a set point or some other command (such as a 0-10V  
BMS signal).  
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11 Operating information  
Sequence of operation (continued)  
OPERATION  
DISPLAY  
8. If the space heating call for heat is active, and the tank thermostat  
or sensor starts a DHW call for heat, the boiler will switch to the  
DHW mode. If programmed for normal DHW operation (not as a  
zone), the DHW pump will turn on rst, then the boiler pump will  
turn off 2 seconds later. This will divert the boiler’s outlet water  
from the heating system and send it to the tank coil instead. The  
control will then modulate to maintain the outlet temperature to  
the DHW boiler set point.  
9. If the boiler is not part of a Cascade, and both the space heating  
and DHW calls for heat remain active long enough, the boiler will  
switch back and forth between the two heating modes until one of  
them is satised.  
10. Once both calls for heat are satised, the control will turn off the  
burner.The blower will continue to run during a 10 second  
postpurge.  
11. Any pumps that are running will continue to run for their respective  
pump delay times before turning off, unless programmed to  
remain on continuously. A 60 second anti-cycle period will start,  
which will delay any new call for heat until it times out.  
12. In Standby, ready to start a new cycle.  
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Installation & Operation Manual  
11 Operating information  
(continued)  
Knight XL control module  
Use the control panel (FIG. 11-1) to set temperatures, operating conditions, and monitor boiler operation.  
Figure 11-1 Control Panel  
NAVIGATION DIAL  
The information on the bottom of the display shows the functions of the two SELECT keys (on either corner), and the  
NAVIGATION dial (in the center):  
MENU = Left SELECT Key  
SETPOINTS = NAVIGATION Dial - Pressing Down  
SHDN = Right SELECT Key  
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11 Operating information  
Access modes  
User  
The user can adjust space heating and tank target temperatures by pressing  
the NAVIGATION dial when “SETPOINTS” is flashing at the bottom  
of the display. The date and time, and the temperature units can also be  
changed (see page 60).  
Installer  
Most parameters are available only to the installer, accessible by entering  
the installer password, see the Knight XL Service Manual.  
Saving parameters (reference the Parameter Table in the Knight  
XL Service Manual)  
Please note that the brackets ([]) denote screen status.  
NOTICE  
To save parameters and exit programming:  
Press the RIGHT SELECT [SAVE] key and then press the RIGHT SELECT  
[HOME] key.  
To enter a parameter and continue programming:  
Press the RIGHT SELECT [SAVE] key 1 time to return to the parameter  
listings; press again to return to the menu listings. Remember to press the  
RIGHT SELECT [HOME] key when finished programming in order to  
save the changes made.  
See the Knight XL Service Manual for a detailed description of parameters  
and access modes.  
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11 Operating information  
(continued)  
Figure 11-2 Status Display Screen  
B
A
(CALL FOR  
HEAT)  
(BOILER  
STATUS)  
C
(OPERATIONAL  
INFORMATION)  
F
D
(LEFT SELECT  
KEY)  
(RIGHT SELECT KEY)  
E
(NAVIGATION DIAL)  
Status Display Screens  
Section  
Display  
Description  
The unit has not received a call for heat from a remote thermostat nor  
has it received a call for heat from a DHW thermostat.  
STANDBY  
START  
The unit has begun a burn cycle and is checking all safety circuits.  
The unit has initiated a 10 second purge period on a call for heat.  
PREPURGE  
IGNITION  
The unit has begun a 4 second spark period to ignite the main burner.  
The unit has fired and is running at the displayed percentage.  
A
%
(Boiler Status  
Bar)  
The call for heat has been satisfied and the unit runs the fan for an  
additional 10 seconds to clear the combustion chamber and vent  
system of residual flue products.  
POSTPURGE  
SHUTDOWN  
The unit has been placed in the OFF position.  
The controlled temperature has exceeded its set point and its offset.  
The unit has detected a condition that has temporarily interrupted  
the current call for heat.  
BLOCKED  
Room Thermostat 1 has a call for heat.  
Room Thermostat 2 has a call for heat.  
Room Thermostat 3 has a call for heat.  
B
The tank thermostat or sensor has a call for heat.  
(Call for Heat  
Indicators)  
Indicates which room thermostat demand shows priority.  
The unit is being controlled by a 0 - 10V BMS signal.  
The member unit is supplying heat while in Cascade Mode.  
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Status Display Screens (cont’d)  
Section  
Display  
Description  
SYSTEM:  
The temperature read by the system supply sensor (if connected).  
TANK:  
The temperature read by the tank sensor (if connected).  
The temperature read by the outdoor sensor (if connected).  
OUTDOOR:  
INLET TEMP:  
OUTLET TEMP:  
DELTA T:  
The temperature read at the inlet to the heat exchanger.  
The temperature read at the outlet of the heat exchanger.  
The temperature difference between the inlet and the outlet of the  
heat exchanger.  
FLUE TEMP:  
The temperature read by the flue sensor.  
FLAME CURRENT:  
The current measured by the flame sense circuit.  
FAN SPEED:  
The speed of the combustion blower.  
C
BOILER PUMP:  
SYSTEM PUMP:  
DHW PUMP:  
The status of the boiler pump output.  
The status of the system pump output.  
The status of the DHW pump output.  
(Operational  
Information)  
BMS VOLTAGE:  
The voltage received from a BMS system.  
BLR PUMP OUTPUT:  
The speed signal sent to a variable speed boiler pump in percent.  
SYS PUMP INPUT:  
The speed signal received from a variable speed system pump control.  
RATE OUTPUT:  
SH RUN HOURS:  
SH CYCLES:  
A 0 - 10V signal indicating the firing rate of the boiler.  
The total hours of operation in the Space Heating Mode.  
The total burner cycles in the Space Heating Mode.  
The total hours of operation in the DHW Mode.  
The total burner cycles in the DHW Mode.  
DHW RUN HOURS:  
DHW CYCLES:  
LAST 10 FAULTS NO:* The last 10 lockouts.  
Press and hold the LEFT SELECT key for 5 seconds to enter the Menu  
Screen.  
MENU  
EXIT  
YES  
Press the LEFT SELECT key to exit the current screen or setting.  
D
Press the LEFT SELECT key to confirm that the boiler needs to  
shutdown.  
(LEFT SELECT  
key function)  
Press the LEFT SELECT key to enter the screen that allows you to  
adjust the limit settings.  
LIMITS  
HOME  
Press the LEFT SELECT key to return to the Status Screen and upload  
parameter changes.  
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11 Operating information  
(continued)  
Status Display Screens (cont’d)  
Section  
Display  
Description  
Turning the NAVIGATION dial will select the next or previous Status  
Screen.  
Pressing the NAVIGATION dial will show the next fault, NSB (Night  
Setback) trigger, or ramp delay setting.  
Pressing the NAVIGATION dial will select the setting indicated by  
the cursor.  
E
(NAVIGATION  
Dial Function)  
Pressing the NAVIGATION dial will display the Set Points Screen.  
Turning the NAVIGATION dial will move the cursor up or down.  
Turning the NAVIGATION dial will increase or decrease the current  
setting.  
SHDN  
ON  
Press the RIGHT SELECT key to turn the boiler OFF.  
Press the RIGHT SELECT key to turn the boiler ON.  
F
NO  
Press the RIGHT SELECT key to cancel the shutdown operation.  
Press the RIGHT SELECT key to save the current change.  
(RIGHT SELECT  
key function)  
SAVE  
HOME  
Press the RIGHT SELECT key to return to the Status Screen and  
upload parameter changes.  
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12 Maintenance  
Maintenance and annual startup  
Table 12A Service and Maintenance Schedules  
Owner maintenance  
Service technician  
(see the Knight XL User’s Information Manual for  
instructions)  
(see the following pages for instructions)  
General:  
• Address reported problems  
• Check boiler area  
• Inspect interior; clean and vacuum if  
necessary;  
Daily  
• Check pressure/temperature  
gauge  
• Clean condensate trap and ll with fresh  
water  
• Check for leaks (water, gas, ue,  
condensate)  
• Verify ue and air lines in good condition  
and sealed tight  
• Check vent piping  
• Check air piping  
• Check system water pressure/system  
piping/expansion tank  
• Check air and vent termination  
screens  
Monthly  
• Check control settings  
• Check ignition and ame sense  
electrodes (sand off any deposits; clean  
and reposition)  
• Check relief valve  
• Check wiring and connections  
• Check condensate drain system  
• Check air vents  
• Perform start-up checkout and  
performance verication per Section 10.  
• Flame inspection (stable, uniform)  
Test low water cutoff (if used)  
• Reset button (low water cutoff)  
Periodically  
• Flame signal (at least 10 microamps at  
high re)  
• Clean the heat exchanger if ue  
temperature is more than 54°F (30°C)  
above return water temperature.  
• Check boiler piping (gas and  
water) for leaks  
If combustion or performance  
indicate need:  
Every  
6 months  
• Clean heat exchanger  
• Operate relief valve  
• Remove and clean burner using  
compressed air only  
• Clean the blower wheel  
End  
of season  
months  
Shut boiler down (unless boiler  
used for domestic hot water)  
72  
Installation & Operation Manual  
12 Maintenance  
(continued)  
Follow the Service and maintenance procedures given throughout this manual and in component literature  
shipped with the boiler. Failure to perform the service and maintenance could result in damage to the boiler  
or system. Failure to follow the directions in this manual and component literature could result in severe  
personal injury, death, or substantial property damage.  
ƽ WARNING  
The boiler should be inspected annually only by a qualified service technician. In addition, the maintenance  
and care of the boiler designated in Table 12A and explained on the following pages must be performed to  
assure maximum boiler efficiency and reliability. Failure to service and maintain the boiler and system could  
result in equipment failure.  
ƽ WARNING  
Electrical shock hazard – Turn off power to the boiler before any service operation on the boiler except as  
noted otherwise in this instruction manual. Failure to turn off electrical power could result in electrical shock,  
causing severe personal injury or death.  
ƽ WARNING  
Address reported problems  
Figure 12-1 Condensate Trap  
1. Inspect any problems reported by the owner and correct  
before proceeding.  
RETAINING  
SCREW  
2” PVC CAP WITH  
BLOCKED DRAIN SWITCH  
Inspect boiler area  
1. Verify that boiler area is free of any combustible materials,  
gasoline and other flammable vapors and liquids.  
PVC TEE ASSEMBLY  
(FACTORY SUPPLIED)  
2. Verify that air intake area is free of any of the contaminants  
listed in Section 1 of this manual. If any of these are  
present in the boiler intake air vicinity, they must be  
removed. If they cannot be removed, reinstall the air  
and vent lines per this manual and the Knight XL Service  
Manual.  
CONDENSATE FROM  
HEAT EXCHANGER  
TO FLOOR  
DRAIN  
Inspect boiler interior  
1. Remove the front access cover and inspect the interior of  
the boiler.  
The condensate trap must be filled with  
water during all times of boiler operation to  
avoid flue gas emission from the condensate  
drain line. Failure to fill the trap could result  
in severe personal injury or death.  
ƽ WARNING  
2. Vacuum any sediment from inside the boiler and  
components. Remove any obstructions.  
Clean condensate trap  
Check all piping for leaks  
Eliminate all system or boiler leaks.  
1. Inspect the condensate drain line, condensate PVC  
fittings, and condensate trap.  
ƽ WARNING  
Continual fresh makeup water will reduce  
boiler life. Minerals can build up in sections,  
reducing heat transfer, overheating heat  
exchanger, and causing heat exchanger  
failure. Leaking water may also cause severe  
property damage.  
2. Remove the PVC cap retaining screw from the PVC cap  
(FIG. 12-1).  
3. Remove the 2 inch PVC cap with the switch located at the  
top of the trap (FIG. 12-1).  
1. Inspect all water and gas piping and verify to be leak free.  
4. Remove any sediment in the trap.  
2. Look for signs of leaking lines and correct any problems  
found.  
5. Fill with fresh water until the water begins to pour out of  
the drain.  
3. Check gas line using the procedure found in Section 7 -  
Gas Connections.  
6. Replace the cap. Press the cap onto the trap until the cap  
makes contact with the drain.  
7. Replace the retaining screw.  
73  
Installation & Operation Manual  
12 Maintenance  
Safety relief valves should be re-inspected  
AT LEAST ONCE EVERY THREE YEARS,  
by a licensed plumbing contractor or  
authorized inspection agency, to ensure  
that the product has not been affected by  
corrosive water conditions and to ensure  
that the valve and discharge line have not  
been altered or tampered with illegally.  
Certain naturally occurring conditions  
may corrode the valve or its components  
over time, rendering the valve inoperative.  
Such conditions are not detectable unless  
the valve and its components are physically  
removed and inspected. This inspection  
must only be conducted by a plumbing  
contractor or authorized inspection agency  
– not by the owner. Failure to re-inspect the  
boiler relief valve as directed could result in  
unsafe pressure buildup, which can result in  
severe personal injury, death, or substantial  
property damage.  
Flue vent system and air piping  
ƽ WARNING  
1. Visually inspect the entire flue gas venting system and air  
piping for blockage, deterioration or leakage. Repair any  
joints that show signs of leakage. Verify that air inlet pipe  
is connected and properly sealed.  
2. Verify that boiler vent discharge and air intake are clean  
and free of obstructions.  
Failure to inspect for the above conditions  
and have them repaired can result in  
severe personal injury or death.  
ƽ WARNING  
Check water system  
1. Verify all system components are correctly installed and  
operational.  
2. Check the cold fill pressure for the system. Verify it is  
correct (must be a minimum of 12 psi (82.7 kPa)).  
3. Watch the system pressure as the boiler heats up (during  
testing) to ensure pressure does not rise too high.  
Excessive pressure rise indicates expansion tank sizing or  
performance problem.  
Following installation, the valve lever must  
be operated AT LEAST ONCE A YEAR to  
ensure that waterways are clear. Certain  
naturally occurring mineral deposits may  
adhere to the valve, rendering it inoperative.  
When manually operating the lever, water  
will discharge and precautions must be  
taken to avoid contact with hot water and  
to avoid water damage. Before operating  
lever, check to see that a discharge line is  
connected to this valve directing the flow  
of hot water from the valve to a proper  
place of disposal. Otherwise severe personal  
injury may result. If no water flows, valve  
is inoperative. Shut down the boiler until a  
new relief valve has been installed.  
ƽ WARNING  
4. Inspect automatic air vents and air separators. Remove  
air vent caps and briefly press push valve to flush vent.  
Replace caps. Make sure vents do not leak. Replace any  
leaking vents.  
Check expansion tank  
1. Expansion tanks provide space for water to move in  
and out as the heating system water expands due to  
temperature increase or contracts as the water cools.  
Tanks may be open, closed or diaphragm or bladder  
type. See Section 6 - Hydronic Piping for suggested best  
location of expansion tanks and air eliminators.  
2. After following the above warning directions, if the relief  
valve weeps or will not seat properly, replace the relief  
valve. Ensure that the reason for relief valve weeping is  
the valve and not over-pressurization of the system due to  
expansion tank waterlogging or undersizing.  
Check boiler relief valve  
1. Inspect the relief valve and lift the lever to verify flow.  
Before operating any relief valve, ensure that it is piped  
with its discharge in a safe area to avoid severe scald  
potential. Read Section 6 - Hydronic Piping before  
proceeding further.  
74  
Installation & Operation Manual  
12 Maintenance  
(continued)  
Inspect ignition and ame sense  
Figure 12-2 Burner Assembly - Model 400  
electrodes  
1. Remove the ignition and flame sense electrodes from the  
boiler heat exchanger access cover.  
2. Remove any deposits accumulated on the ignition/flame  
sense electrode using sandpaper. If the electrodes cannot  
be cleaned satisfactorily, replace with new ones.  
AIR / GAS ARM  
3. Replace ignition/flame sense electrode, making sure  
gasket is in good condition and correctly positioned.  
Check ignition ground wiring  
1. Inspect boiler ground wire from the heat exchanger  
BURNER  
GASKET  
access cover to ground terminal strip.  
2. Verify all wiring is in good condition and securely  
attached.  
SCREWS  
(QTY. 5)  
3. Check ground continuity of wiring using continuity  
meter.  
Figure 12-3 Burner Assembly - Model 501  
4. Replace ground wires if ground continuity is not  
satisfactory.  
Check all boiler wiring  
1. Inspect all boiler wiring, making sure wires are in good  
AIR / GAS ARM  
condition and securely attached.  
Check control settings  
1. Set the SMART SYSTEM control module display to  
Parameter Mode and check all settings. See Section  
1 of the Knight XL Service Manual. Adjust settings if  
necessary. See Section 1 of the Knight XL Service Manual  
for adjustment procedures.  
BURNER  
GASKET  
SCREWS  
(QTY. 5)  
2. Check settings of external limit controls (if any) and  
adjust if necessary.  
Figure 12-4 Burner Assembly - Models 601 - 801  
Perform start-up and checks  
1. Start boiler and perform checks and tests specified in  
Section 10 - Start-up.  
2. Verify cold fill pressure is correct and that operating  
pressure does not go too high.  
AIR ARM  
Check burner ame  
1. Inspect flame through observation window.  
2. If the flame is unsatisfactory at either high fire or low fire,  
turn off boiler and allow boiler to cool down. Remove  
the burner and clean it thoroughly using a vacuum  
cleaner or compressed air. Do not use compressed air to  
clean burner if performed inside a building.  
BURNER  
GASKET  
SCREWS  
(QTY. 5)  
3. Remove the burner, reference FIG.’s 12-2 thru 12-4.  
4. When replacing the burner, ensure gasket is in good  
condition and positioned correctly (FIG.’s 12-2 thru  
12-4).  
75  
Installation & Operation Manual  
12 Maintenance  
6. Use a vacuum cleaner to remove any accumulation on the  
boiler heating surfaces. Do not use any solvent.  
7. Brush the heat exchanger while dry using a nylon bristle  
brush. Caution: DO NOT use a metal brush. Re-vacuum  
the heat exchanger.  
8. Finish cleaning using a clean cloth dampened with warm  
water. Rinse out debris with a low pressure water supply.  
9. Allow the heat exchanger to thoroughly dry.  
10. Remove the field supplied rear refractory cover from the  
back of the combustion chamber of the heat exchanger and  
reassemble.  
11. Close isolation valves on piping to isolate boiler from  
system. Attach a hose to the boiler drain and flush boiler  
thoroughly with clean water by using purging valves to  
allow water to flow through the water make-up line to the  
boiler.  
Check ame signal  
1. At high fire the flame signal shown on the display should  
be at least 10 microamps.  
2. A lower flame signal may indicate a fouled or damaged  
flame sense electrode. If cleaning the flame sense electrode  
does not improve, ground wiring is in good condition,  
and ground continuity is satisfactory, replace the flame  
sense electrode.  
3. See Section 3 - Troubleshooting in the Knight XL Service  
Manual for other procedures to deal with low flame  
signal.  
Review with owner  
1. Review the Knight XL User’s Information Manual with  
the owner.  
12. Perform start-up and check-out procedures in the Check  
Flame and Combustion - Section 10 - Startup on pages 57  
and 59 of this manual.  
2. Emphasize the need to perform the maintenance schedule  
specified in the Knight XL User’s Information Manual  
(and in this manual as well).  
13. Replace the access cover and restore boiler to operation.  
3. Remind the owner of the need to call a licensed contractor  
should the boiler or system exhibit any unusual behavior.  
Table 12B Heat Exchanger Cleaning Kits  
4. Remind the owner to follow the proper shutdown  
procedure and to schedule an annual start-up at the  
beginning of the next heating season.  
Kit  
Part  
Component  
Description  
Model  
Number Number  
CTN20005  
Rear Refractory Cover  
Nylon 4" Wheel Brush*  
MSC20083*  
Cleaning boiler heat exchanger  
For recommended materials; including brush, appropriate  
extension(s), refractory cover, and detailed instructions see  
Table 12B - Heat Exchanger Cleaning Kits.  
400  
KIT30063  
MSC20084  
3mm Allen Wrench  
1/4" x 24" Drill Extension  
Rear Refractory Cover  
Nylon 4" Wheel Brush*  
1/4" x 12" Drill Extension  
1/4" x 24" Drill Extension  
MSC20086  
CTN20005  
MSC20083*  
KIT30064  
1. Shut down boiler:  
501 - 801  
• Follow the “To Turn Off Gas to Appliance” instructions  
for the boiler in Section 10 - Startup.  
MSC20085  
MSC20086  
• Do not drain the boiler unless it will be exposed to  
freezing temperatures. If using freeze prevention fluid  
in system, do not drain.  
* Do NOT use a metal brush. Only use  
the kit provided brush or an equivalent  
replacement nylon brush.  
ƽ CAUTION  
2. Allow time for the boiler to cool to room temperature if  
it has been firing.  
Figure 12-5 Rope Gasket - Heat Exchanger Door  
3. Remove the nuts securing the heat exchanger access cover  
to the heat exchanger and set aside.  
4. Remove the heat exchanger access cover, burner, and  
gas/air arm assembly.  
ROPE GASKET  
The boiler contains ceramic fiber  
ƽ WARNING  
materials. Use care when handling these  
materials per instructions in the Service  
Manual. Failure to comply could result in  
severe personal injury.  
CAUTION: IF GASKET IS DAMAGED  
DO NOT REUSE, THE HEAT EXCHANGER DOOR  
MUST BE REPLACED.  
5. Remove the condensate hose from the heat exchanger  
end. Connect a field supplied 3/4” diameter hose to  
a drain pan. Using field supplied means, cover the  
refractory in the back of the combustion chamber of the  
heat exchanger.  
Rope gasket is intended for sealing combustion  
(FIG. 12-5). If damaged DO NOT reuse, the  
heat exchanger door must be replaced. Consult  
factory for replacement heat exchanger door  
(kit WTR3080 and WTR3086).  
NOTICE  
76  
Installation & Operation Manual  
13 Diagrams  
Figure 13-1 Wiring Diagram  
LOW VOLTAGE  
120 VAC  
HIGH VOLTAGE  
BOX DEPICTS  
OPTIONAL ITEMS  
BOX DEPICTS  
DUAL SENSOR  
SINGLE HOUSING  
INTEGRATED  
CONTROL  
CONNECTION BOARD  
L
N
ALARM  
CONTACTS  
1
2
JUNCTION  
BOX  
RELAY  
X-7  
DHW  
BOARD  
PUMP  
RUN-TIME  
3
CN2-4  
CN2-2  
CN1-5  
OR  
CONTACTS  
X1-3 OR  
4
K1  
24 VAC LOUVER  
5
CN1-6  
CN1-3  
OR  
BR  
RELAY COIL  
BOILER  
PUMP  
6
BR  
X1-4  
X1-2  
K2  
K3  
LOUVER  
7
CN5-1  
CN5-8  
CN5-2  
CN5-9  
CN5-3  
CN5-10  
CN5-11  
CN5-4  
CN5-5  
CN5-14  
CN5-12  
CN5-6  
CN5-13  
CN5-7  
BK  
BK  
BK  
BK  
BK  
BK  
BK  
BK  
BK  
X4-7  
X4-14  
X4-6  
PROVING SWITCH  
CN1-4  
CN1-1  
8
BR  
PR  
CN2-3  
PR  
GAS PRESSURE  
9
SWITCH  
SYSTEM  
PUMP  
10  
X4-13  
X4-5  
CN2-1  
CN1-2  
PR  
X4-12  
X4-11  
X4-4  
ON/OFF  
SWITCH  
L
X1-6  
X1-5  
BK  
W
120V  
GND  
N
FLOW  
SWITCH  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
X4-3  
SUPPLY  
BK  
X4-8  
BK  
BK  
BK  
BK  
TANK  
THERMOSTAT  
HEAT/LOOP  
X4-10  
X4-2  
X4-9  
G
R
X1-8  
X1-1  
1
2
3
DEMAND  
X4-1  
HEAT/LOOP  
DEMAND  
HEAT/LOOP  
TRANSFORMER  
3.5A  
DEMAND  
RW G  
3
SYSTEM  
SENSOR  
OUTDOOR  
SENSOR  
21  
22  
23  
24  
25  
26  
27  
28  
29  
30  
31  
32  
KB 801  
ONLY  
1
2
BLOWER  
TANK  
SENSOR  
1
2
3
4
5
SHIELD  
A
CASCADE  
B
SHIELD  
X5-7  
X5-16  
X5-8  
R
T
CN6  
X6  
W
BK  
Y
BMS  
33  
34  
35  
36  
37  
38  
39  
40  
41  
42  
43  
44  
+
0-10V  
X5-15  
X5-9  
IN  
-
SYS PUMP  
+
0-10V  
IN  
-
BLR PUMP  
X5-1  
BL  
O
+
0-10V  
OUT  
-
X5-2  
RATE  
+
O-TEMP HEX SW  
0-10V  
BLOCKED DRAIN SWITCH  
OUT  
-
X5-10  
X5-11  
X5-4  
P
SHIELD  
AIR PRESSURE SWITCH  
A
O/BK  
R/BK  
GY  
MODBUS  
OPTION  
-T  
-T  
-T  
-T  
-T  
B
OPERATING SENSOR S1a  
HIGH LIMIT SENSOR S1b  
SHIELD  
X5-12  
X5-6  
24 VAC  
COM  
CN7-1  
LOW  
WATER  
CUT-OFF  
P/BK  
W/BK  
PR  
INLET SENSOR S2  
FLUE SENSOR S3a  
FLUE SENSOR S3b  
CN7-2  
CN7-3  
CN7-4  
X5-5  
X5-13  
X5-14  
RBLG  
Y
X2-2  
BK  
Y
GAS VALVE  
@24VAC  
O
GY  
G
X4-1  
X4-2  
X4-3  
X4-4  
X9-1  
X9-2  
X9-3  
X9-4  
X2-1  
X1-7  
TR2  
MODBUS BOARD  
MTR-01  
W/R  
FLAME SENSOR  
SPARK  
ROD  
G
SHIELD  
GROUNDING  
JUMPER  
X5-1  
X5-2  
CAUTION HIGH VOLTAGE SPARK LEAD  
BK  
W
G
X1-1  
X1-2  
X1-3  
Notes:  
1. All wiring must be installed in accordance with: local, state, provincial and national code requirements per either N.E.C. in USA or C.S.A. in Canada.  
2. If any original equipment wire as supplied with the appliance must be replaced, it must be replaced with wire having same wire gauge (AWG) and rated for a  
minimum of 105°C. Exceptions: Replacement high vo ltage spark lead and ribbon cables must be purchased from the factory. Use of a non-approved spark lead  
or ribbon cables can lead to operational problems which could result in non-repairable damage to the integrated controller or other components.  
3. Actual connector block locations may vary from those shown on diagrams. Refer to actual components for proper connector block locations when using  
diagrams to troubleshoot unit.  
WIRING DIAGRAM  
LBL20116 REV C  
77  
Installation & Operation Manual  
13 Diagrams  
Figure 13-2 Ladder Diagram  
JUNCTION BOX  
120VAC  
NEUTRAL  
TERMINAL STRIP  
120V SUPPLY "L"  
TERMINAL STRIP  
120V SUPPLY "N"  
L
IN  
L
OUT  
GROUND  
SYSTEM  
INTEGRATED CONTROL  
PUMP  
ON / OFF  
SWITCH  
CONTACTS  
BLOWER  
2
1
X1-1  
X1-2  
X1-6  
F2  
3.15A  
SYSTEM  
PUMP  
3
BOILER  
PUMP  
CONTACTS  
F1  
5A  
SYSTEM PUMP  
RELAY  
SYSTEM PUMP  
RELAY  
X1-3  
BOILER  
PUMP  
DHW PUMP  
RELAY  
DHW PUMP  
RELAY  
DHW  
PUMP  
CONTACTS  
X1-4  
BOILER PUMP  
RELAY  
BOILER PUMP  
RELAY  
F3  
DHW  
PUMP  
.8A  
24V DC  
SUPPLY  
RELAY BOARD  
X5-9  
X5-1  
120 VAC  
24 VAC  
X4-3  
3.5A  
KB 801 ONLY  
CONNECTION BOARD  
INTEGRATED  
CONTROL  
CN5-5  
FLOW  
CN5-14 X4-8  
CN5-10 X4-12  
LWCO  
CN7-1  
CN7-3  
CN7-4  
CN7-2  
11  
SWITCH  
12  
CONNECTION BOARD  
HEAT/LOOP  
DEMAND  
1
CN5-7  
X4-1  
19  
17  
20  
18  
HEAT/LOOP  
DEMAND 2  
CN5-13 X4-9  
HEAT/LOOP  
DEMAND  
3
CN5-6  
X4-2  
15  
13  
16  
14  
TANK  
THERMOSTAT  
CN5-12  
X4-10  
LOW GAS  
PRESSURE  
SWITCH  
HIGH GAS  
PRESSURE  
SWITCH  
CN5-11  
CN5-3  
X4-11  
X4-5  
10  
9
5
INTEGRATED  
CONTROL  
LOUVER  
RELAY COIL  
6
7
24VAC  
LOUVER  
PROVING SWITCH  
CN5-4  
X4-4  
X7  
8
RIBBON CABLE  
X5-2  
BLOCKED  
X5-10  
X5-11  
O-TEMP HEX SW  
PC INTERFACE  
DRAIN SWITCH  
X5-6  
X5-4  
S2  
INLET  
SENSOR  
AIR PRESSURE  
SWITCH  
S1a  
S1b  
S3a  
OPERATING  
SENSOR  
1
X5-12  
X5-5  
HIGH LIMIT  
SENSOR  
GAS VALVE  
X2-2  
X2-1  
2
FLUE  
SENSOR  
GAS VALVE  
RELAY  
6
X5-13  
X5-14  
S3b  
FLUE  
SENSOR  
BLOWER  
1
2
4
5
X5-7  
X5-16  
X5-8  
13  
CONNECTION  
BOARD  
CN5-1  
CN5-8  
X4-7  
1
2
ALARM  
CONTACTS  
X4-14  
X5-15  
CN5-2  
CN5-9  
X4-6  
3
4
RUN-TIME  
CONTACTS  
X4-13  
TR2  
CN6  
CN6  
CN6  
X6  
X6  
X6  
S6  
21  
22  
X1-7  
SYSTEM  
SENSOR  
S5  
FLAME ROD  
23  
24  
26  
27  
29  
30  
31  
32  
33  
34  
35  
36  
37  
38  
39  
40  
41  
42  
43  
44  
OUTDOOR  
SENSOR  
SPARK  
ROD  
CN3-9  
X4-9  
S4  
TANK  
SENSOR  
CN3-6  
X4-6  
SHIELD  
CAUTION HIGH VOLTAGE SPARK LEAD  
CN6  
X6  
A
CASCADE  
B
CN6  
CN6  
X6  
X6  
NOTES:  
1. Where possible, switches are shown without utilities (gas, water or  
electricity) connected to the unit. As such, actual switch states may  
vary from those shown on diagrams depending upon whether utilities  
are connected or a fault condition is present.  
SHIELD  
CN6  
CN6  
CN6  
X6  
X6  
X6  
BMS  
+
0-10V  
IN  
-
+
-
SYS PUMP  
IN  
2. See wiring diagram for additional notes.  
0-10V  
0-10V  
0-10V  
CN6  
CN6  
X6  
X6  
+
-
BLR PUMP  
OUT  
CN6  
CN6  
X6  
X6  
BOX DEPICTS  
OPTIONAL ITEMS  
+
-
RATE  
OUT  
LOW VOLTAGE  
120 VAC  
HIGH VOLTAGE  
M
O
D
B
U
S
SHIELD  
CN8-1  
CN8-2  
CN8-3  
X6-1  
X4-1  
X9-2  
X9-1  
X9-3  
A
MODBUS  
X6-2  
X6-3  
X4-2  
X4-3  
B
LADDER DIAGRAM  
LBL20141 REV C  
SHIELD  
78  
Installation & Operation Manual  
Notes  
79  
Revision Notes: Revision A (ECO #C05747) initial release. Reects  
the new model numbers for the Knight XL upgrade.  
Revision B (ECO #C06188) reects changes made to FIG. 6-10 (ECR  
#R03474) remove ghost pipe, changes made to FIG.’s 6-7, 6-9, and  
6-11 (R03563) change the direction of the arrows, and edits made to  
the ladder and wiring diagrams (ECO #C06158).  
Revision C (ECO #C06234) reects changes made to the Service  
Reminder feature.  
Revision D (ECO #C07981) reects the layout in InDesign, edits made  
ECR04077 - combustible water pipes change from 1” to a 1/4”, changes  
made to Table 3B on page 20, ECR03940 - addition of the rope gasket  
warning, ECR03740 - changes made to FIG’s 7-1 thru 7-4 pages 46  
and 47, changes made to Table 3A on page 18, ECR03727 - 400 - 601  
reference applied incorrectly on pages 15 and 16, add O-temp switch.  
KBXII-I-O Rev D  
5/11  

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