Energy Tech Laboratories DHG240 User Manual

INSTALLATION  
INSTRUCTION  
SUNLINE GAS/ELECTRIC  
SINGLE PACKAGE  
AIR CONDITIONERS  
CONTENTS  
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3  
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . 3  
AGENCY APPROVALS . . . . . . . . . . . . . . . . . . . . . . 4  
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . 25  
COMPLETE TABLE OF CONTENTS ON FOLLOWING PAGE  
MODELS: DHG180 (15 TON, 10.0 EER)  
DHG240 (20 TON, 9.7 EER)  
208/230/460 VOLT  
208/230/575 VOLT  
MODELS ONLY  
MODELS ONLY  
SAVE THIS MANUAL  
035-17233-000-C-0702  
035-17233-000-C-0702  
D 1 HG 180 E 180 25 EC  
TABLE 1: PRODUCT NOMENCLATURE  
Model Number  
Description  
Model #  
Options  
D
1
Product Category  
Product Generation  
Product Identifier  
D = Air Cond., Single Package  
1 = 1st Generation  
HG = Gas/Electric  
HG  
180  
Nominal Cooling Capacity  
180 = 15 Tons  
240 = 20 Tons  
A = No Heat  
E = Electric Heat  
E
Factory Installed Heat  
Nominal Heating Capacity  
Voltage Code  
N = Natural Gas  
018 = 18 kW  
036 = 36 kW  
054 = 54 kW  
072 = 72 kW  
018  
25  
25 = 208/230-3-60  
58 = 575-3-60  
46 = 460-3-60  
EC = Single Input Economizer  
DK = Dual Input Economizer  
FD = Sing. Input Economizer w/ Power CF = Dual Input Economizer with Power  
Factory Installed  
Option Code  
EC  
Exhaust  
Exhaust  
BG = Motorized Outdoor Air Damper  
GENERAL  
SAFETY CONSIDERATIONS  
YORK Model DHG units are single package high efficiency  
gas-fired central heating furnaces with cooling unit designed  
for outdoor installation on a rooftop or a slab.  
Installer should pay particular attention to the words: NOTE,  
CAUTION, and WARNING. Notes are intended to clarify or  
make the installation easier. Cautions are given to prevent  
equipment damage. Warnings are given to alert installer that  
personal injury and/or equipment damage may result if instal-  
lation procedure is not handled properly.  
The units are completely assembled on rigid, permanently  
attached base rails. All piping, refrigerant charge, and electri-  
cal wiring is factory installed and tested. The units require  
electric power, gas connection, duct connections, installation  
of combustion air inlet hood, flue gas outlet hoods and fixed  
outdoor air intake damper (units without economizer or  
motorized damper option only) at the point of installation.  
Due to system pressure, moving parts and electrical compo-  
nents, installation and servicing of air conditioning equipment  
can be hazardous. Only qualified, trained, service personnel  
should install, repair, maintain or service this equipment.  
The gas-fired heaters have aluminized-steel tubular heat  
exchangers and spark ignition with proven pilot.  
Observe all precautions in the literature, on labels and tags  
accompanying the equipment whenever working on air condi-  
tioning equipment. Be sure to follow all other safety precau-  
tions that apply.  
.
Wear safety glasses and work gloves, and follow all safety  
codes. Use a quenching cloth and have a fire extinguisher  
available for all brazing operations.  
FOR YOUR SAFETY IF YOU SMELL GAS:  
a. Open windows.  
b. Don’t touch electrical switches; do not use any  
phones in the area of the gas leak.  
c. Extinguish any open flame.  
This product must be installed in strict compliance  
with the enclosed installation instructions and any  
applicable local, state, and national codes includ-  
ing, but not limited to, building, electrical and  
mechanical codes.  
d. Immediately call your gas supplier from another  
location. Follow your gas supplier’s instructions.  
e. If you cannot reach your gas supplier, call the fire  
departments.  
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035-17233-000-C-0702  
INSTALLATION  
LIMITATIONS  
Improper installation may create a condition where  
the operation of the product could cause personal  
injury or property damage.  
These units must be installed in accordance with the follow-  
ing national and local safety codes:  
1. National Electrical Code ANSI/NFPA No. 70.  
2. National Fuel Gas Code Z223.1.  
REFERENCE  
3. Gas-Fired Central Furnace Standard ANSI Z21.47a.  
4. Local gas utility requirements.  
Additional information on the design, installation, operation  
and service of this equipment is available in the following ref-  
erence forms:  
Refer to Table 2 for Unit Application Data and to Table 4 for  
Gas Heat Application Data.  
44-320-10 - Barometric Relief Damper Accessory  
530.18-N6.1V - Propane Conversion Accessory (USA)  
530.18-N6.2V - High Altitude Accessory (Nat. Gas)  
530.18-N6.3V - High Altitude Accessory (Propane)  
TABLE 2: UNIT APPLICATION DATA  
MODEL SIZE  
208/230-3-60  
15 TON  
20 TON  
RENEWAL PARTS:  
187/253  
Refer to the Renewal Parts Manual for complete listing of  
replacement parts on this equipment.  
Voltage Variation,  
460-3-60  
575-3-60  
414/506  
518/630  
1
Min./Max  
All forms referenced in this instruction may be ordered from:  
Supply Air CFM, Min./Max.  
4500/7200  
6000/9400  
Wet Bulb Temperature (°F) of air  
on Outdoor Coil Min./Max.  
57/72  
Standard Register  
2101 West Tecumseh Road  
Norman, Oklahoma 73069  
Toll Free Phone (877) 318-9675  
Toll Free Fax: (877) 379-7920  
Dry Bulb Temperature (°F) of air  
25/120  
2
on Outdoor Coil Min./Max.  
1
Rated in accordance with ARI Standard 110, utilization  
range “A”.  
AGENCY APPROVALS  
2
A low ambient accessory is available for operation  
down to 0°F.  
Design certified by ETL as follows:  
After installation, the unit must be adjusted to obtain a tem-  
perature rise within the range specified on the unit rating  
plate.  
1. For use as a forced air furnace with cooling unit.  
2. For outdoor installation only.  
3. For installation on combustible material.  
4. For use with natural gas or propane gas.  
If components are to be added to a unit to meet local codes,  
they are to be installed at the dealer's and/or the customer's  
expense.  
INSPECTION  
Size of unit for proposed installation should be based on heat  
loss/heat gain calculation made according to the methods of  
the Air Conditioning Contractors of America (ACCA).  
As soon as a unit is received, it should be inspected for possi-  
ble damage during transit. If damage is evident, the extent of  
the damage should be noted on the carrier's freight bill. A  
separate request for inspection by the carrier's agent should  
be made in writing. Refer to Form 50.15-NM for additional  
information.  
This furnace is not to be used for temporary heating of build-  
ings or structures under construction.  
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LOCATION  
Use the following guidelines to select a suitable location for  
these units.  
Length of the forks must be a minimum of 90”.  
1. Unit is designed for outdoor installation only.  
2. Condenser coils must have an unlimited supply of air.  
Where a choice of location is possible, position the unit  
on either north or east side of building.  
An adhesive backed label is provided over the out-  
side of the combustion air inlet opening to prevent  
moisture from entering the unit which could cause  
damage to electrical components. Allow this clo-  
sure label to remain in place until the combustion  
air hood is to be installed (refer to Figure 7).  
Excessive exposure of this furnace to contami-  
nated combustion air may result equipment dam-  
age or personal injury. Typical contaminates  
include: permanent wave solutions, chlorinated  
waxes and cleaners, chlorine based swimming  
pool chemicals, water softening chemicals, carbon  
tetrachloride, Halogen type refrigerants, cleaning  
solvents (e.g. perchloroethylene), printing inks,  
paint removers, varnishes, hydrochloric acid,  
cements and glues, antistatic fabric softeners for  
clothes dryers, masonry acid washing materials.  
3. For ground level installation, use a level concrete slab  
with a minimum thickness of 4 inches. The length and  
width should be at least 6 inches greater than the unit  
base rails. Do not tie slab to the building foundation.  
4. Roof structures must be able to support the weight of the  
unit and its options and/or accessories. Unit must be  
installed on a solid level roof curb or appropriate angle  
iron frame.  
FIGURE 1: TYPICAL RIGGING  
Refer to Table 6 for unit weights and to Figure 2 for approxi-  
mate center of gravity.  
If a unit is to be installed on a roof curb or special  
frame other than a YORK roof curb, gasketing  
must be applied to all surfaces that come in con-  
tact with the unit underside.  
5. Maintain level tolerance to 1/2" maximum across the  
entire length or width of the unit.  
RIGGING AND HANDLING  
Exercise care when moving the unit. Do not remove any  
packaging until the unit is near the place of installation. Rig  
the unit by attaching chain or cable slings to the round lifting  
holes provided in the base rails. Spreaders, whose length  
exceeds the largest dimension across the unit, MUST be  
used across the top of the unit. Refer to Figure 1.  
FIGURE 2 : CENTER OF GRAVITY  
CLEARANCES  
Units may also be moved or lifted with a forklift, from the front  
or rear only, providing that an accessory skid is used.  
All units require certain clearances for proper operation and  
service. Installer must make provisions for adequate  
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035-17233-000-C-0702  
combustion and ventilation air in accordance with Section  
5.3, Air for Combustion and Ventilation of the National Fuel  
Gas Code, ANSI Z223.1 (in U.S.A.) or Sections 7.2, 7.3 or  
7.4 of Gas Installation Codes CAN/CGA-B149.1 and .2 (in  
Canada) and/or applicable provisions of the local building  
codes. Refer to Table 8 for the clearances required for  
combustible construction, servicing, and proper unit  
operation.  
Do not permit overhanging structures or shrubs to  
obstruct outdoor air discharge outlet, combustion  
air inlet or vent outlets.  
FIGURE 3 : FIXED OUTDOOR AIR DAMPER  
DUCTWORK  
Gasketing and mounting screws are provided in a parts bag  
attached to the hood assembly. Apply gasketing to the three  
flange surfaces on the hood prior to installing the hood.  
Extend gasketing 1/4" beyond the top and bottom of the two  
side flanges to insure adequate sealing.  
Ductwork should be designed and sized according to the  
methods in Manual Q of the Air Conditioning Contractors of  
America (ACCA).  
A closed return duct system shall be used. This shall not pre-  
clude use of economizers or outdoor fresh air intake. The  
supply and return air duct connections at the unit should be  
made with flexible joints to minimize noise.  
Adjusting the damper to the desired air flow may be done  
before mounting the hood into position or (after installation)  
by removing the front hood panel or the screen on the bottom  
of the hood. Damper baffle in position 1 will allow approxi-  
mately 10% recirculated air flow, position 2 approximately  
15% and, to allow approximately 25%, remove the damper  
baffle.  
The supply and return air duct systems should be designed  
for the CFM and static requirements of the job. They should  
NOT be sized to match the dimensions of the duct connec-  
tions on the unit.  
On units with bottom return air applications, install the  
damper assembly over the opening in the side return air  
access panel. Remove and discard the opening cover and  
the covering over the hood mounting holes (used for ship-  
ping) before installing. Secure with the screws provided.  
When fastening ductwork to side duct flanges on  
unit, insert screws through duct flanges only. DO  
NOT insert screws through casing.  
On units with side return air applications, install the damper  
assembly on the return air ductwork as close to the unit as  
possible. Cut an opening 16" high by 18" wide in the ductwork  
to accommodate the damper. Using the holes in the hood  
flanges as a template, drill 9/64" dia. (#26 drill) holes into the  
Outdoor ductwork must be insulated and water-  
proofed.  
ductwork and secure with the screws provided.  
Refer to Figure 10 and 12 for information concerning side and  
bottom supply and return air duct openings.  
FIXED OUTDOOR AIR INTAKE DAMPER  
This damper is shipped inside the return air compartment. It  
is completely assembled and ready for installation. A damper  
baffle inside of the hood is adjustable to provide variable  
amounts of outdoor air intake on units that are not provided  
with an economizer or a motorized damper option. Refer to  
Figure 3.  
If outdoor air intake will not be required on units  
with bottom return air applications, the damper  
assembly should still be mounted on the side  
return air access panel, per the instructions above,  
to insure moisture is not drawn into the unit during  
operation. The covering over the mounting holes  
only need be removed. Do not remove the opening  
cover.  
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Side Supply & Return Air compartments (Two panels)  
Blower compartment (Three panels)  
Main control box  
Filter compartment  
Outdoor Air compartment (Two panels)  
CONDENSATE DRAIN  
Plumbing must conform to local codes. Use a sealing com-  
pound on male pipe threads. Install a condensate drain line  
from the 1" NPT female connection on the unit to an open  
drain.  
Refer to Figure 10 for location of these access panels.  
Make sure that all screws and panel latches are  
replaced and properly positioned on the unit to  
maintain an air-tight seal.  
THERMOSTAT  
The room thermostat should be located on an inside wall  
approximately 56" above the floor where it will not be subject  
to drafts, sun exposure or heat from electrical fixtures or  
appliances. Follow manufacturer's instructions enclosed with  
thermostat for general installation procedure. Seven color  
coded insulated wires (#18 AWG) should be used to connect  
thermostat to unit.  
FIGURE 4 : RECOMMENDED DRAIN PIPING  
An alternate drain connection (1" NPT female coupling) is  
provided inboard on the same centerline as the exterior loca-  
tion.  
NOTE: The condensate drain line MUST be trapped to pro-  
vide proper drainage. See Figure 4.  
POWER AND CONTROL WIRING  
COMPRESSORS  
Field wiring to the unit must conform to provisions of the  
National Electrical Code, ANSI / NFPA No. 70 (latest edition)  
and/or local ordinances. The unit must be electrically  
grounded in accordance with N.E.C. and/or local codes. Volt-  
age tolerances which must be maintained at the compressor  
terminals during starting and running conditions are indicated  
on the unit Rating Plate and Table 2.  
Units are shipped with compressor mountings factory-  
adjusted and ready for operation.  
The internal wiring harness furnished with this unit is an inte-  
gral part of a ETL design certified unit. Field alteration to com-  
ply with electrical codes should not be required.  
Do Not loosen compressor mounting bolts.  
FILTERS  
A fused disconnect switch should be field provided for the  
unit. The switch must be separate from all other circuits. Wire  
entry at knockout openings require conduit fittings to comply  
with NEC and/or local codes. Refer to Figure 10 for installa-  
tion location. If any of the wire supplied with the unit must be  
replaced, replacement wire must be of the type shown on the  
wiring diagram and the same minimum gauge as the  
replaced wire.  
Two-inch filters are supplied with each unit. Filters must  
always be installed ahead of the evaporator coil and must be  
kept clean or replaced with same size and type. Dirty filters  
will reduce the capacity of the unit and will result in frosted  
coils or safety shutdown. Minimum filter area and required  
sizes are shown in Table 6.  
SERVICE ACCESS  
Electrical line must be sized properly to carry the load. Each  
unit must be wired with a separate branch circuit fed directly  
Access to all serviceable components are provided by the fol-  
lowing removable panels:  
from the meter panel and properly fused.  
Refer to Figure 5 for typical field wiring and to the appropriate  
unit wiring diagram for control circuit and power wiring infor-  
mation.  
Compressor compartment  
Gas Heat compartment (Two panels)  
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035-17233-000-C-0702  
Typical supply piping arrangements are shown in Figures 6  
and 7. All shaded items are field-supplied.  
Two grommets are shipped in the blower compartment (in  
parts bag taped to the blower housing) of every unit with gas  
heat and should be used in the knockouts when the gas pip-  
ing penetrates the front of the unit.  
When connecting electrical power and control wir-  
ing to the unit, waterproof type connectors MUST  
BE USED so that water or moisture cannot be  
drawn into the unit during normal operation. The  
above waterproofing conditions will also apply  
when installing a field-supplied disconnect switch.  
After the gas supply piping has been installed, the bottom  
opening in the unit should be sealed to prevent water from  
leaking into the building.  
COMBUSTION DISCHARGE  
Gas piping recommendations:  
The products of combustion are discharged horizontally  
through two screened (hooded) openings on the upper gas  
1. A drip leg and a ground joint union must be installed in  
the gas piping.  
heat access panel.  
2. When required by local codes, a manual shut-off valve  
may have to be installed outside of the unit.  
TABLE 3: CONTROL WIRE SIZES1  
2
Wire Size  
3. Use wrought iron or steel pipe for all gas lines. Pipe dope  
should be applied sparingly to male threads only.  
22  
40  
20  
19  
18  
16  
120  
150  
190  
305  
4. All piping should be cleaned of dirt and scale by ham-  
mering on the outside of the pipe and blowing out the  
loose dirt and scale. Before initial start-up, be sure that  
all of the gas lines external to the unit have been purged  
of air.  
3
Max. Wire Length Feet  
1
Total wire length is from unit to room thermostat, and  
back to unit.  
2
3
Solid, Class II copper wire.  
Total Wire length is from unit to room thermostat, and  
back to unit.  
5. The gas supply should be a separate line and installed in  
accordance with all safety codes as prescribed under  
Limitations. After the gas connections have been com-  
pleted, open the main shut-off valve admitting normal  
gas pressure to the mains. Check all joints for leaks with  
soap solution or other material suitable for the purpose.  
NEVER USE A FLAME.  
GAS PIPING  
Proper sizing of gas piping depends on the cubic feet per  
hour of gas flow required, specific gravity of the gas and the  
length of run. National Fuel Gas Code Z223.1 should be fol-  
lowed in all cases unless superseded by local codes or gas  
utility requirements. Refer to Table 5.  
6. The furnace and its individual manual shut-off valve must  
be disconnected from the gas supply piping system dur-  
ing any pressure testing of that system at test pressures  
in excess of 1/2 psig (3.48kPa).  
The heating value of the gas may differ with locality. The  
value should be checked with the local gas utility.  
The furnace must be isolated from the gas supply piping  
system by closing its individual manual shut-off valve  
during any pressure testing of the gas supply piping sys-  
tem at test pressures equal to or less than 1/2 psig  
(3.48kPa).  
NOTE: There may be a local gas utility requirement specify-  
ing a minimum diameter for gas piping. All units require a 1  
inch pipe connection at the entrance fitting.  
GAS CONNECTION  
7. A 1/8 inch NPT plugged tapping, accessible for test gage  
connection, must be installed immediately upstream of  
the gas supply connection to the furnace.  
The gas supply line can be routed through the knockouts  
located on the front of the unit or through the opening pro-  
vided in the unit's base. Refer to Figure 10 to locate these  
access openings.  
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FIGURE 5 : TYPICAL FIELD WIRING  
TABLE 4: GAS HEAT APPLICATION DATA1  
Input Capacity (Mbh)  
Output Capacity (Mbh)  
Temp Rise °F  
2
0 to 2000 Feet  
0 to 2000 Feet  
3
2,000 to 4,500 Feet  
Above Sea Level  
2,000 to 4,500 Feet  
Above Sea Level  
Available on  
Models  
Gas Rate  
3
At Full Input  
4
4
Above Sea Level  
Above Sea Level  
(Ft. /Hr.)  
Min.  
300  
400  
Max.  
150  
Min.  
270  
360  
Max.  
135  
Min.  
240  
320  
Max.  
213  
Min.  
20  
Max.  
50  
15 & 20 Ton  
15 & 20 Ton  
279  
372  
200  
180  
281  
30  
60  
1
Heaters are shipped available fro natural gas, but can be converted to L.P./Propane with Kit Model No. 1NP0418.  
2
3
4
3
Based on maximum input and 1075/Btu/Ft.  
The air flow must be adjusted to obtain a temperature rise within the range shown.  
MBH rating should be reduced at the rate of 4 percent for each 1,000 feet above 4,500 feet.  
Unitary Products  
9
035-17233-000-C-0702  
TABLE 5: PIPE SIZING1  
Nominal Iron Pipe Size  
Length in Feet  
1 in.  
1-1/4 in.  
1,050  
730  
10  
20  
30  
40  
50  
60  
70  
80  
90  
100  
520  
350  
285  
245  
215  
195  
180  
170  
160  
150  
590  
500  
440  
400  
370  
350  
320  
305  
FIGURE 7 : BOTTOM SUPPLY CONNECTION  
1
Maximum capacity of pipe in cubic feet of gas per hour.  
(Based upon a pressure drop of 0.3 inch water column  
and 0.6 specific gravity gas.)  
EXTERNAL SHUT-OFF  
L.P. UNITS, TANKS AND PIPING  
All gas heat units are shipped from the factory equipped for  
natural gas use only. The unit may be converted in the field  
for use with L.P./propane gas with accessory kit model num-  
ber 1NP0437.  
All L.P./propane gas equipment must conform to the safety  
standards of the National Fire Protection Association.  
For satisfactory operation, L.P./propane gas pressure must  
be 8.8 inch W.C at the unit under full load. Maintaining proper  
gas pressure depends on three main factors:  
1. The vaporization rate which depends on (a) the tempera-  
ture of the liquid and (b) the wetted surface area of the  
container or containers.  
2. The proper pressure regulation. (Two-stage regulation is  
recommended from the standpoint of both cost and effi-  
ciency.)  
FIGURE 6 : EXTERNAL SUPPLY CONNECTION  
EXTERNAL SHUT-OFF  
3. The pressure drop in the lines between regulators and  
between the second stage regulator and the appliance.  
Pipe size required will depend on the length of the pipe  
run and the total load of all appliances.  
Complete information regarding tank sizing for vaporization,  
recommended regulator settings, and pipe sizing is available  
from most regulator manufacturers and L.P./propane gas  
suppliers.  
Natural gas may contain some propane. Propane,  
being an excellent solvent, will quickly dissolve  
white lead or most standard commercial com-  
pounds. Therefore, a special pipe compound must  
be applied when wrought iron or steel pipe is used.  
Shellac base compounds such as Gaskolac or  
Stalastic, and compounds such as Rectorseal #5,  
Cyde's or John Crane may be used.  
L.P./propane gas is an excellent solvent and special pipe  
compound must be used when assembling piping for this gas  
as it will quickly dissolve white lead or most standard com-  
mercial compounds. Shellac base compounds such as Rec-  
torseal #5 are satisfactory for this type of gas.  
10  
Unitary Products  
035-17233-000-C-0702  
Check all connections for leaks when piping is completed,  
using a soap solution. NEVER USE A FLAME.  
The outdoor and return air dampers, the damper actuator, the  
damper linkage, the outdoor and return air divider baffles,  
and all the control sensors are factory mounted as part of the  
Factory installed economizer option.  
VENT AND COMBUSTION AIR HOODS  
ENTHALPY SET POINT ADJUSTMENT  
Two vent hoods and a combustion air hood (with screens) are  
shipped attached to the blower housing in the blower com-  
partment. These hoods must be installed to assure proper  
unit function. All hoods must be fastened to the outside of the  
gas heat access panel with the screws provided in the bag  
also attached to the blower housing.  
Remove the economizer access panel from the unit to check  
the following adjustments. Loosen but do not remove the two  
panel latches.  
The screen for the combustion air intake hood is secured as  
shown on the label attached to the hood. The top flange of  
this hood slips in under the top of the access panel opening  
when installing. Refer to Figure 8.  
Extreme care must be exercised in turning both  
the setpoint and minimum position adjusting  
screws to prevent twisting them off.  
Each vent hood is installed by inserting the top flange of the  
hood into the slotted opening in the access panel and secur-  
ing in place.  
1. The enthalpy set point may now be set by selecting the  
desired setpoint shown in Figure 9. Adjust as follows:  
For a single enthalpy operation, carefully turn the set  
point adjusting screw to the A, B, C or D setting corre-  
sponding to the lettered curve.  
For a dual enthalpy operation, carefully turn the set point  
adjusting screw fully clockwise past the D setting.  
SLOTTED  
OPENINGS IN  
ACCESS PANEL  
2. To check that the damper blades move smoothly without  
binding, carefully turn the minimum position adjusting  
screw fully clockwise and then energize and de-energize  
terminals R to G. With terminals R to G energized, turn  
the minimum position screw counterclockwise until the  
desired minimum position has been attained.  
VENT AIR  
OUTLET  
HOODS  
3. Replace the economizer access panel. Reposition the  
two latches horizontally and retighten the screws.  
COMBUSTION  
AIR INTAKE  
HOOD  
POWER EXHAUST/BAROMETRIC RELIEF DAMPER  
AND RAIN HOOD OPTION  
GAS HEAT  
ACCESS  
PANELS  
The instructions for the power exhaust/barometric relief  
damper and rain hood can be found in form 44-320-10. The  
exhaust fan, all supporting brackets, angles, and the wiring  
are factory installed as part of the power exhaust option.  
FIGURE 8 : VENT AND COMBUSTION AIR  
HOODS  
All of the components, including the dampers, hardware, and  
mounting instructions are shipped in a single package exter-  
nal from the unit. The hood must be field assembled and  
installed.  
OPTIONAL ECONOMIZER/MOTORIZED DAMPER  
RAIN HOOD  
Power exhaust is not available as a field installed option.  
The instruction for the optional economizer/motorized  
damper rain hood can be found in form 44-320-2. Use these  
instructions when field assembling an economizer rain hood  
onto a unit.  
Unitary Products  
11  
035-17233-000-C-0702  
FIGURE 9 : ENTHALPY SETPOINT ADJUSTMENT  
12  
Unitary Products  
035-17233-000-C-0702  
TABLE 7: DHG VOLTAGE LIMITATIONS1  
TABLE 6: PHYSICAL DATA  
DHG  
VOLTAGE  
MODELS  
POWER SUPPLY  
MIN.  
180  
240  
MAX.  
253  
Centrifugal Blower (Dia. x Wd. in.)  
15 x 15 18 x 15  
EVAPORATOR  
BLOWER  
208/230-3-60  
460-3-60  
187  
414  
518  
Fan Motor HP  
Rows Deep  
5
4
7.5  
4
506  
506  
575-3-60  
EVAPORATOR  
COIL  
Fins Per Inch  
13.5  
15.5  
30  
13.5  
20.0  
30  
1
Utilization Range “A” in accordance with ARI Standard  
110.  
Face Area (Sq. Ft.  
Propeller Dia. (in.) (Each)  
Fan Motor Hp (Each)  
CONDENSER  
FANS  
1
1
(Two Per Unit)  
Nom. CFM (Each)  
5765  
3
7000  
3
TABLE 8: MINIMUM CLEARANCES  
Rows Deep (Each)  
CONDENSER  
COILS  
(Two Per Unit)  
LOCATION  
CLEARANCE  
Fins Per Inch (Each)  
13  
15  
36”  
Front  
Face Area (Sq. Ft.) (Total)  
10-Ton Tandem Hermetic Recip.  
5-Ton Hermetic Recip.  
Quantity Per Unit (16” X 20” X 2”)  
Quantity Per Unit (16” X 25” X 2”)  
Quantity Per Unit (18” X 24” X 2”)  
Total Face Area (sq. ft.)  
36.0  
43.3  
2
24” (Less Economizer)  
49” (With Economizer  
Back  
1
COMPRESSOR  
(Qty. Per Unit)  
1
24” (Less Economizer)  
36” (With Economizer)  
1
-
-
4
Left Side (Filter Access)  
Right Side (Cond. Coil)  
36”  
0”  
-
4
AIR  
FILTERS  
1
Below Unit  
5
-
72” With 36” Maximum  
Horizontal Overhang (For  
Condenser Air Discharge)  
15.0  
29/9  
14/8  
2100  
2140  
20.0  
23  
2
Above Unit  
System #1  
Refrigerant 22  
CHARGE  
(lbs./oz.)  
System #2  
240Mbh (lbs)  
320Mbh (lbs)  
23/12  
2300  
2340  
1
Units may be installed on combustible floors made  
from wood or class A, B, or C roof covering material.  
BASIC  
UNIT  
DHG  
(Gas/Electric)  
2
Units must be installed outdoors. Overhanging struc-  
tures or shrubs should not obstruct condenser air dis-  
charge outlet.  
Economizer (lbs)  
160  
245  
150  
Economizer with  
Power Exhaust (lbs)  
OPTIONS  
Motorized Damper (lbs)  
Roof Curb (lbs)  
175  
45  
185  
45  
ACCY.  
Barometric Damper (lbs)  
Wood Skid (lbs)  
220  
220  
1
This compressor will be energized first.  
TABLE 9: DHG ELECTRICAL DATA  
COMPRESSORS  
COND. FAN  
MOTORS  
(#1 & #2)  
SUPPLY AIR  
BLOWER  
MOTOR  
MIN.  
MAX. TIME  
DELAY FUSE  
SIZE (AMPS)  
1
POWER  
SUPPLY  
#1 #2  
CIRCUIT  
AMPACITY  
(AMPS)  
MIN. WIRE  
MODEL  
SIZE 75°C  
HP  
FLA  
(ea.)  
RLA  
LRA  
RLA  
LRA  
HP  
FLA  
(ea.)  
208/230-3-60  
460-3-60  
28.6  
14.4  
11.4  
28.6  
14.4  
11.4  
274  
138  
116  
274  
138  
116  
14.3  
7.2  
137  
69  
1
1
1
1
1
1
4.1/4.2  
2.1  
5
5
11.8  
5.9  
77.8/77.0  
42.7  
90  
50  
4
8
8
3
6
8
DHG180  
575-3-60  
5.7  
58  
1.4  
5
5.2  
30.7  
35  
208/230-3-60  
460-3-60  
28.6  
14.4  
11.4  
274  
138  
116  
4.1/4.2  
2.1  
7.5  
7.5  
7.5  
18.6  
9.3  
98.6/96.8  
52.2  
110  
60  
DHG240  
575-3-60  
1.4  
7.5  
40.2  
45  
1
Although these sizes are based on copper conductors aluminum wire can be used. Refer to the national electric code (in USA) or  
the current Canadian Electrical Code (in Canada) to determine the proper size.  
Unitary Products  
13  
035-17233-000-C-0702  
ECONOMIZER / MOTORIZED DAMPER,  
FIXED OUTDOOR INTAKE AIR AND  
POWER EXHAUST RAIN HOODS  
(See detail "Y")  
BLOWER  
ACCESS  
FIELD-SUPPLIED  
DISCONNECT SWITCH  
LOCATION  
BLOWER MOTOR  
ACCESS  
COMPRESSOR  
ACCESS  
BLOWER  
COMPARTMENT  
ACCESS  
(Auxiliary)  
OPTIONAL COIL  
GUARD KIT  
DOT PLUG  
(For pressure  
Drop Reading)  
48-5/8" (15 Ton)  
52-5/8" (20 Ton)  
GAS HEAT  
ACCESS  
CONDENSER  
COILS  
VENT AIR  
OUTLET  
HOODS  
21"  
5"  
7-1/8"  
COMBUSTION  
AIR INLET  
HOOD  
125-1/4" (15 Ton)  
136-1/4" (20 Ton)  
6-3/8"  
9-3/4"  
5-7/8"  
92"  
(C)  
(A)  
GAS SUPPLY  
CONTROL WIRING  
ENTRY  
ENTRY  
46-5/8"  
CONTROL BOX  
ACCESS  
11-1/2"  
(B)  
35"  
POWER WIRING  
ENTRY  
BOTTOM SUPPLY  
AND RETURN  
AIR OPENINGS  
(See Note)  
FRONT  
VIEW  
24-1/4" (15 Ton)  
35-1/4" (20 Ton)  
RETURN AIR  
SUPPLY AIR  
OUTDOOR AIR  
RETURN  
AIR  
3-3/4"  
33"  
SUPPLY  
AIR  
2-3/4"  
21-1/2"  
11-1/8"  
OUTDOOR AIR  
(Economizer)  
UNIT BASE WITH RAILS  
(B)  
(D)  
Shown separately to illustrate  
Bottom Duct openings, Power  
and Gas Piping Connection  
locations  
POWER WIRING  
ENTRY  
GAS SUPPLY  
ENTRY  
All dimensions are in inches. They are  
subject to change without notice. Certi-  
fied dimensions will be provided upon  
request.  
(A)  
CONTROL WIRING  
ENTRY  
8-1/8"  
9-3/4"  
NOTE:  
46-5/8"  
For curb mounted units, refer to the curb hanger  
dimensions of the curb for the proper size of the  
supply and return air duct connections.  
9-1/4"  
12-1/2"  
FIGURE 10 : UNIT DIMENSIONS DHG180 & 240 (FRONT VIEW)  
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FIGURE 11 : UNIT DIMENSIONS DHE/DHG180 & 240 (RAINHOOD)  
14  
Unitary Products  
035-17233-000-C-0702  
C
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T
D
O
O
R
O
O
N
N
D
N
.
E
D
R
A
I
I
N
C
C
E
S
S
I
R
C
T
O
N
S
A
U
C
P
C
P
L
Y
A
I
R
E
S
S
4
0
-
1
/
2
"
1
8
-
5
/
8
"
R
E
A
R
V
I
E
W
2
7
-
3
/
4
"
5
-
1
/
8
"
O
C
A
U
T
M
D
O
O
R
T
A
I
R
R
A
E
T
C
U
R
N
S
A
I
R
O
P
A
R
M
E
N
T
C
E
S
C
C
E
S
S
2
3
8
9
-
-
5
5
/
/
8
8
"
"
(
(
1
2
5
0
T
T
o
o
n
n
s
s
)
)
FIGURE 12 : UNIT DIMENSIONS DHE/DHG180 & 240 (REAR VIEW)  
NOTE: A 1” clearance must be provided between any com-  
bustible material and the supply air ductwork for a distance of  
3 feet from the unit.  
2. Remove and discard the bottom duct covers. (Duct  
openings are closed with sheet metal covers except  
when the unit includes a power exhaust option. The cov-  
ering consists of a heavy black paper composition.)  
NOTE: The products of combustion must not be allowed to  
accumulate within a confined space and recirculate.  
TABLE 10: UTILITIES ENTRY  
OPENING SIZE  
HOLE  
USED FOR  
NOTE: Locate unit so that the vent air outlet hood is at least:  
(DIA.)  
1-1/8” KO  
Front  
Three (3) feet above any force air inlet located within 10  
horizontal feet (excluding those integral to the unit).  
A
B
Control Wiring  
3/4” NPS (Fem.)  
3-5/8” KO  
Bottom  
Front  
Bottom  
1
Power Wiring  
Four (4) feet below, 4 horizontal feet from, or 1 foot  
above any door or gravity air inlet into the building.  
3” NPS (Fem.)  
C
D
2-3/8” KO  
Gas Piping (Front)  
1,  
2
1-11/16” Hole  
Four (4) feet from electric and gas meters, regulators  
and relief equipment  
Gas Pipping (Bottom)  
1
1” Gas Piping MPT Required.  
2
NOTE: All entry holes should be field sealed to prevent rain  
water entry into building  
Opening in the bottom to the unit can be located by the  
side in the insulation.  
3. Replace the side supply and return air compartment pan-  
els.  
Duct Covers - Units are shipped with the bottom duct open-  
ings covered. An accessory flange kit is available for con-  
necting side ducts.  
For side duct applications:  
For bottom duct applications:  
1. Replace the side panels on the supply and return air  
compartments with the accessory flange kit panels.  
1. Remove the side panels from the supply and return air  
compartments.  
2. Connect ductwork to the duct flanges on the rear of the  
unit.  
Unitary Products  
15  
035-17233-000-C-0702  
TABLE 11: DHG 15 TON SUPPLY AIR BLOWER PERFORMANCE  
1, 2  
DHG180 - BOTTOM DUCT CONNECTIONS  
MOTOR  
PULLEY  
(TURNS  
CFM  
BLOWER  
SPEED,  
(RPM)  
4500  
BHP  
5250  
BHP  
6000  
6750  
BHP  
7200  
4
3
3
3
3
KW  
KW  
BHP  
KW  
KW  
BHP  
KW  
3
ESP  
ESP  
ESP  
ESP  
ESP  
OPEN)  
208 VOLT AND STANDARD DRIVE  
5
850  
870  
0.9  
1.0  
1.1  
1.2  
1.3  
1.4  
1.6  
2.4  
2.5  
2.6  
2.7  
2.9  
3.0  
3.2  
2.1  
2.2  
2.4  
2.5  
2.6  
2.7  
2.9  
0.6  
0.7  
0.8  
0.9  
1.0  
1.1  
1.3  
2.9  
3.0  
3.1  
3.2  
3.4  
3.6  
3.8  
2.6  
2.7  
2.8  
2.9  
3.0  
3.2  
3.4  
0.3  
0.4  
0.5  
0.6  
0.7  
0.8  
1.0  
3.4  
3.5  
3.6  
3.7  
3.8  
4.0  
4.4  
3.0  
3.1  
3.2  
3.3  
3.4  
3.6  
3.9  
-
-
-
-
-
-
6.0  
5.5  
4.5  
3.5  
3.0  
2.0  
1.0  
-
-
-
-
-
-
915  
0.2  
0.4  
0.5  
0.6  
0.8  
4.1  
4.4  
4.5  
4.7  
5.0  
3.7  
3.9  
4.0  
4.2  
4.5  
-
-
-
965  
0.2  
0.3  
0.4  
0.6  
5.0  
5.1  
5.4  
5.6  
4.5  
4.6  
4.8  
5.0  
980  
1010  
1040  
FIGURE 13 : 208 VOLT AND HIGH SPEED DRIVE ACCESSORY  
965  
6.0  
5.5  
4.5  
3.5  
2.0  
1.0  
1.2  
1.3  
1.4  
1.6  
1.9  
2.1  
2.7  
2.9  
3.1  
3.4  
3.6  
3.9  
2.5  
2.6  
2.8  
3.0  
3.2  
3.5  
0.9  
1.0  
1.2  
1.4  
1.7  
1.9  
3.2  
3.4  
3.6  
3.9  
4.4  
4.7  
2.9  
3.0  
3.2  
3.5  
3.9  
4.2  
0.6  
0.7  
0.9  
1.1  
1.4  
1.6  
3.7  
3.8  
4.1  
4.5  
5.0  
5.5  
3.3  
3.4  
3.7  
4.0  
4.5  
4.9  
0.4  
0.5  
0.7  
0.9  
1.2  
-
4.4  
4.5  
4.8  
5.1  
5.8  
-
3.9  
4.0  
4.3  
4.6  
5.2  
-
0.2  
0.3  
0.4  
-
5.0  
5.1  
5.5  
-
4.5  
4.6  
4.9  
-
980  
1025  
1065  
1125  
1170  
-
-
-
-
-
-
230/460 VOLT AND STANDARD DRIVE  
4
870  
915  
1.0  
1.1  
1.2  
1.3  
1.4  
1.5  
1.6  
2.5  
2.6  
2.7  
2.9  
3.0  
3.1  
3.4  
2.2  
2.4  
2.5  
2.6  
2.7  
2.8  
3.0  
0.7  
0.8  
0.9  
1.0  
1.1  
1.2  
1.4  
3.0  
3.1  
3.2  
3.4  
3.6  
3.7  
3.9  
2.7  
2.8  
2.9  
3.0  
3.2  
3.3  
3.5  
0.4  
0.5  
0.6  
0.7  
0.8  
0.9  
1.1  
3.5  
3.6  
3.7  
3.8  
4.0  
4.2  
4.5  
3.1  
3.2  
3.3  
3.4  
3.6  
3.8  
4.0  
-
-
-
-
-
-
6.0  
5.0  
4.0  
3.5  
2.5  
1.5  
1.0  
0.2  
0.4  
0.5  
0.6  
0.7  
0.9  
4.1  
4.4  
4.5  
4.7  
4.9  
5.1  
3.7  
3.9  
4.0  
4.2  
4.4  
4.6  
-
-
-
965  
0.2  
0.3  
0.4  
0.5  
-
5.0  
5.1  
5.4  
5.7  
-
4.5  
4.6  
4.8  
5.1  
-
980  
1015  
1050  
1065  
230/460 VOLT AND HIGH SPEED DRIVE ACCESSORY  
980  
6.0  
4.5  
4.0  
2.5  
1.5  
1.0  
1.3  
1.6  
1.7  
1.9  
2.1  
2.2  
2.9  
3.2  
3.4  
3.6  
3.9  
4.0  
2.6  
2.9  
3.0  
3.2  
3.5  
3.6  
1.0  
1.3  
1.4  
1.7  
1.8  
1.9  
3.4  
3.8  
3.9  
4.4  
4.7  
4.8  
3.0  
3.4  
3.5  
3.9  
4.2  
4.3  
0.7  
1.0  
1.1  
1.4  
1.6  
1.7  
3.8  
4.4  
4.5  
5.0  
5.5  
5.6  
3.4  
3.9  
4.0  
4.5  
4.9  
5.0  
0.5  
0.8  
0.9  
1.2  
-
4.5  
5.0  
5.1  
5.8  
-
4.0  
4.5  
4.6  
5.2  
-
0.3  
5.1  
4.6  
1045  
1065  
1125  
1170  
1190  
0.6  
5.6  
5.0  
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1
Blower performance includes a gas -fired heat exchanger, fixed outdoor air, 2” T/A filters and a dry evaporator coil.  
Refer to the Static Resistance table.  
2
3
4
DO NOT close the pulley below one turn open.  
ESP = External Static Pressure available for the supply and return air duct system. All internal unit resistances have been  
deducted from the total static pressure of the blower.  
5
The factory setting.  
16  
Unitary Products  
035-17233-000-C-0702  
TABLE 12: DHG 20 TON SUPPLY AIR BLOWER PERFORMANCE  
1, 2  
DHG240 - BOTTOM DUCT CONNECTIONS  
MOTOR  
PULLEY  
(TURNS  
CFM  
BLOWER  
SPEED,  
(RPM)  
6000  
BHP  
7000  
BHP  
8000  
9000  
BHP  
9400  
BHP  
4
4
4
4
4
KW  
KW  
BHP  
KW  
KW  
KW  
3
ESP  
ESP  
ESP  
ESP  
ESP  
OPEN)  
208 VOLT AND STANDARD DRIVE  
5
870  
900  
930  
950  
980  
995  
1015  
1.3  
1.4  
1.6  
1.7  
1.9  
2.1  
2.2  
3.6  
3.8  
4.1  
4.2  
4.5  
4.6  
4.8  
3.0  
3.2  
3.4  
3.6  
3.8  
3.9  
4.0  
0.7  
0.9  
1.1  
1.3  
1.5  
1.6  
1.7  
4.3  
4.7  
5.0  
5.1  
5.4  
5.5  
5.7  
3.7  
4.0  
4.2  
4.3  
4.5  
4.7  
4.8  
0.2  
0.4  
0.6  
0.8  
1.0  
1.1  
1.2  
5.1  
5.6  
5.9  
6.0  
6.3  
6.4  
6.6  
4.3  
4.7  
5.0  
5.1  
5.3  
5.4  
5.6  
-
-
-
-
-
-
6.0  
5.0  
4.0  
3.0  
2.0  
1.5  
1.0  
-
-
-
-
-
-
-
-
-
0.1  
0.2  
0.4  
0.5  
0.7  
6.7  
6.9  
7.2  
7.5  
7.8  
5.7  
5.8  
6.1  
6.3  
6.6  
-
-
-
0.1  
0.2  
-
8.5  
8.6  
-
7.1  
7.3  
-
208 VOLT AND HIGH SPEED DRIVE ACCESSORY  
950  
980  
6.0  
5.0  
4.5  
3.5  
2.5  
2.0  
1.0  
1.7  
1.9  
2.1  
2.3  
2.5  
2.6  
2.9  
4.2  
4.5  
4.6  
4.9  
5.1  
5.3  
5.6  
3.6  
3.8  
3.9  
4.1  
4.3  
4.4  
4.7  
1.3  
1.5  
1.6  
1.8  
2.0  
2.1  
2.3  
5.1  
5.4  
5.5  
5.8  
6.1  
6.3  
6.8  
4.3  
4.5  
4.7  
4.9  
5.1  
5.3  
5.7  
0.8  
1.0  
1.1  
1.3  
1.4  
1.5  
1.8  
6.0  
6.3  
6.4  
6.7  
7.1  
7.3  
7.9  
5.1  
5.3  
5.4  
5.7  
6.0  
6.2  
6.6  
0.2  
0.4  
0.5  
0.7  
0.9  
1.0  
-
6.9  
7.2  
7.5  
8.0  
8.4  
8.6  
-
5.8  
6.1  
6.3  
6.7  
7.0  
7.2  
-
-
-
-
0.1  
8.5  
7.1  
995  
0.2  
8.6  
7.3  
1025  
1050  
1065  
1100  
-
-
-
-
-
-
-
-
-
-
-
-
230/460 VOLT AND STANDARD DRIVE  
5
870  
900  
1.3  
1.4  
1.6  
1.7  
1.9  
2.1  
2.2  
2.3  
3.6  
3.8  
4.1  
4.2  
4.5  
4.6  
4.8  
4.9  
3.0  
3.2  
3.4  
3.6  
3.8  
3.9  
4.0  
4.1  
0.7  
0.9  
1.1  
1.3  
1.5  
1.6  
1.7  
1.8  
4.3  
4.7  
5.0  
5.1  
5.4  
5.5  
5.7  
5.8  
3.7  
4.0  
4.2  
4.3  
4.5  
4.7  
4.8  
4.9  
0.2  
0.4  
0.6  
0.8  
1.0  
1.1  
1.2  
1.3  
5.1  
5.6  
5.9  
6.0  
6.3  
6.4  
6.6  
6.7  
4.3  
4.7  
5.0  
5.1  
5.3  
5.4  
5.6  
5.7  
-
-
-
-
-
-
6.0  
5.0  
4.0  
3.5  
2.5  
2.0  
1.5  
1.0  
-
-
-
-
-
-
930  
0.1  
0.2  
0.4  
0.5  
0.6  
0.7  
6.7  
6.9  
7.2  
7.5  
7.8  
8.0  
5.7  
5.8  
6.1  
6.3  
6.6  
6.7  
-
-
-
-
-
-
950  
965  
0.1  
0.2  
-
8.5  
8.6  
-
7.1  
7.3  
-
995  
1015  
1025  
-
-
-
230/460 VOLT AND HIGH SPEED DRIVE ACCESSORY  
950  
980  
6.0  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
1.5  
1.0  
1.7  
1.9  
2.1  
2.2  
2.3  
2.5  
2.6  
2.9  
3.1  
4.2  
4.5  
4.6  
4.8  
4.9  
5.1  
5.3  
5.6  
5.8  
3.6  
3.8  
3.9  
4.0  
4.1  
4.3  
4.4  
4.7  
4.9  
1.3  
1.5  
1.6  
1.7  
1.8  
2.0  
2.1  
2.3  
2.5  
5.1  
5.4  
5.5  
5.7  
5.8  
6.1  
6.3  
6.8  
7.0  
4.3  
4.5  
4.7  
4.8  
4.9  
5.1  
5.3  
5.7  
5.9  
0.8  
1.0  
1.1  
1.2  
1.3  
1.4  
1.5  
1.8  
1.9  
6.0  
6.3  
6.4  
6.6  
6.7  
7.1  
7.3  
7.9  
8.3  
5.1  
5.3  
5.4  
5.6  
5.7  
6.0  
6.2  
6.6  
6.9  
0.2  
0.4  
0.5  
0.6  
0.7  
0.9  
1.0  
-
6.9  
7.2  
7.5  
7.8  
8.0  
8.4  
8.6  
-
5.8  
6.1  
6.3  
6.6  
6.7  
7.0  
7.2  
-
-
-
-
0.1  
8.5  
7.1  
995  
0.2  
8.6  
7.3  
1015  
1025  
1050  
1065  
1100  
1120  
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1
Blower performance includes a gas -fired heat exchanger, fixed outdoor air, 2” T/A filters and a dry evaporator coil.  
Refer to the Static Resistance table.  
2
3
4
DO NOT close the pulley below one turn open.  
ESP = External Static Pressure available for the supply and return air duct system. All internal unit resistances have been  
deducted from the total static pressure of the blower.  
5
The Factory Setting  
Unitary Products  
17  
035-17233-000-C-0702  
TABLE 13: STATIC RESISTANCES1  
RESISTANCE, IWG  
CFM  
DESCRIPTION  
15 TON  
5765  
0.1  
20 TON  
7000  
0.1  
4500  
7200  
0.1  
6000  
9400  
0.1  
WET COIL  
0.1  
0.1  
0.2  
0.1  
0.1  
0.2  
ECONOMIZER OPTION  
0.1  
0.1  
0.1  
0.1  
2
0.3  
0.5  
0.3  
0.5  
HORIZONTAL DUCT CONN.  
1
Deduct these resistance values from the available unit ESP values listed in the respective blower per-  
formance table except for Horizontal Duct Connections.  
2
Add these values due to less airflow resistance.  
TABLE 14: POWER EXHAUST PERFORMANCE  
STATIC RESISTANCE OF RETURN DUCTWORK, IWG  
MOTOR  
0.2  
0.3 0.4 0.5  
0.6  
kW  
1
SPEED  
CFM  
5250  
4900  
4400  
kW  
0.83  
0.77  
0.72  
CFM  
4500  
3900  
3700  
kW  
0.85  
0.79  
0.74  
CFM  
4200  
3500  
3000  
kW  
0.88  
0.82  
0.78  
CFM  
3750  
2900  
-
kW  
0.93  
0.85  
-
CFM  
2
3000  
0.99  
HIGH  
MEDIUM  
LOW  
-
-
-
-
1
Power exhaust motor is a 3/4 HP, PSC type with sleeve bearings, a 48 frame and inherent protection.  
The factory setting.  
2
TABLE 15: BLOWER MOTOR AND DRIVE DATA  
BELT  
(NOTCHED)  
1
ADJ. MOTOR PULLEY  
FIXED BLOWER PULLEY  
MOTOR  
BLWR  
DRIVE RANGE  
(RPM)  
MODEL  
SIZE  
PITCH  
DIA  
(in.)  
PITCH  
DIA  
(in.)  
PITCH  
LNGTH. QTY.  
(in.)  
EFF. DESIGN- O/D  
(%) NATION (in.)  
BORE DESIGN- O/D  
BORE DESIG-  
HP FRAME  
(in.)  
NATION  
(in.)  
(in.)  
NATION  
Std.  
850/1065  
965/1190  
870/1025  
950/1120  
BK90  
8.75  
8.4  
1
BX70  
71.8  
69.8  
84.8  
81.8  
1
1
1
1
4.3-  
High  
Spd.  
Acs.  
15 Ton  
20 Ton  
5
184T  
213T  
89.5  
91  
1VP56  
1VP68  
5.35  
6.75  
1-1/8  
2
5.3  
BK80  
BK120  
BK110  
7.75  
7.4  
1
BX68  
BX83  
BX80  
Std.  
11.75 11.4 1-3/16  
10.75 10.4 1-3/16  
5.5-  
High  
Spd.  
Acs.  
7.5  
1-3/8  
2
6.5  
1
2
All motors have a nominal speed of 1800 RPM, a 1.15 service factor and a solid base. They can operate to the limit of their service  
factor because they are located in the moving air, upstream of any heating device.  
DO NOT close this pulley below 1 turn.  
18  
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035-17233-000-C-0702  
modulate to maintain a constant supply air temperature as  
monitored by the discharge air sensor. If the outdoor air  
enthalpy is above the setpoint, Y1 energizes compressor #1,  
condenser fan motor #1, and condenser fan motor #2 (if the  
ambient temperature is above 60°F).  
OPERATION  
COOLING SYSTEM  
The cooling section is a complete factory package utilizing an  
air-cooled condenser. The system is factory-charged with  
Refrigerant-22.  
When the thermostat calls for second-stage cooling, the low  
voltage control circuit from R to Y2 is completed. If the  
enthalpy of the outdoor air is below the setpoint of the  
enthalpy controller (i.e. first stage has energized the econo-  
mizer), Y2 will energize compressor #1. If the outdoor air is  
above the setpoint, Y2 will energize compressor #2.  
The compressors are hermetically sealed, internally sprung  
and base-mounted with rubber-insulated hold-down bolts.  
Compressors have inherent (internal) protection. If there is an  
abnormal temperature rise in a compressor, the protector will  
open to shut down the compressor.  
After the thermostat is satisfied and opens, all components  
will stop simultaneously. The blower motor will continue to  
operate if the fan switch on the room thermostat is set in the  
ON position.  
PRELIMINARY OPERATION COOLING  
After installation has been completed, energize the crank-  
case heaters for at least four hours before operating the unit.  
After the initial installation, the compressors should be given  
three false starts (energized just long enough to make a few  
revolutions) with 5-7 minutes delay between each start,  
before being put into full time service.  
ECONOMIZER WITH DUAL ENTHALPY SENSORS  
The operation with the dual enthalpy sensors is identical to  
the single sensor except that a second enthalpy sensor is  
mounted in the return air. This return air sensor allows the  
economizer to choose between outdoor air and return air,  
whichever has the lowest enthalpy value, to provide maxi-  
mum operating efficiency.  
NOTE: Prior to each cooling season, the crankcase heaters  
must be energized at least 8 hours before system is put into  
operation.  
ECONOMIZER (SINGLE OR DUAL) WITH POWER  
EXHAUST  
COOLING SEQUENCE OF OPERATION  
NO OUTDOOR AIR OPTIONS  
This system operates as specified above with one addition.  
The power exhaust motor is energized whenever the econo-  
mizer is chosen by the enthalpy sensor for first stage cooling,  
Y1. As always, the R to G connection provides minimum  
position but does not provide power exhaust operation.  
When the room thermostat calls for first-stage cooling, the  
low voltage control circuit from R to G and Y1 is completed to  
energize compressor #1, condenser fan motor #1, condenser  
fan motor #2 (if the ambient temperature is above 60F), and  
the supply air blower motor (if the fan switch on the room  
thermostat is set in the AUTO position).  
MOTORIZED OUTDOOR AIR DAMPERS  
This system operation is the same as the units with no out-  
door air options with one exception. When the R to G circuit is  
complete, the motorized damper drives open to a position set  
by the thumbwheel on the damper motor. When the R to G  
circuit is opened, the damper spring returns fully closed.  
When the thermostat calls for second-stage cooling, the low  
voltage control circuit from R to Y2 is completed to energize  
compressor #2.  
CONTINUOUS BLOWER  
After the thermostat is satisfied and opens, all components  
will stop simultaneously. The blower motor will continue to  
operate if the fan switch on the room thermostat is set in the  
ON position.  
Continuous blower operation is possible by closing the R to G  
circuit on the thermostat.  
SAFETY CONTROLS  
ECONOMIZER WITH SINGLE ENTHALPY SENSOR  
1. A Suction Line Freezestat to protect against low evapo-  
rator temperatures due to a low air flow or a low return  
air temperature. (Opens at 26°F + 5°F and resets at 38°F  
+ 5°F)  
When the room thermostat calls for first-stage cooling, the  
low voltage control circuit from R to G and Y1 is completed.  
The R to G circuit energizes the blower motor (if the fan  
switch on the room thermostat is set in the AUTO position)  
and drives the economizer dampers from fully closed to their  
minimum position. If the enthalpy of the outdoor air is below  
the setpoint of the enthalpy controller (previously  
determined), Y1 energizes the economizer. The dampers will  
2. A High Pressure Cutout Switch to protect against exces-  
sive discharge pressures due to a blocked condenser  
coil or a condenser motor failure. (Opens at 380 psig +  
10 and resets at 300 psig +10)  
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035-17233-000-C-0702  
3. A Low Pressure Switch/Loss Of Charge to protect  
against loss of refrigerant charge. (Opens at 7 psig + 3  
and resets at 22 psig + 5)  
Gas flows into each of the main burners and is ignited from  
the carryover tube flame.  
If IC1 fails to detect a pilot flame, it will continue to try for a  
maximum of 85 seconds to ignite the pilot tube. If the pilot  
flame is not detected, then IC1 will lock out first stage furnace  
operation until 24V power is removed from the module either  
at the unit or by resetting the room thermostat.  
If either one of the above safety controls opens, that individ-  
ual refrigerant system will be locked out. The other refrigerant  
system will continue in operation unless it too is effected by  
the same fault. The lock out of either system can be reset by  
opening the 24V circuit either at the room thermostat or at the  
unit disconnect.  
At the same time power was supplied to the RW1, a parallel  
circuit activates ETD which closes the ETD contact after  
approximately 35 seconds and energizes K5 which closes  
K5-2 and starts the blower by energizing M3.  
HEATING SYSTEM  
The following sequence describes the operation of the gas  
heat section.  
When TH2 closes, heat relay RW2 is energized. The RW2-1  
contact is closed energizing the second stage ignition module  
IC2. IC2 will immediately start the second stage ignitor spark-  
ing and will open the redundant valve located inside the sec-  
ond stage main gas valve GV2 to allow a flow of gas to the  
second stage carryover tube. See Figure 11. Only after the  
pilot flame has been ignited and the presence of pilot flame  
detected at IC2 by a signal sent back through the flame sen-  
sor is sparking terminated and the main gas valve opened.  
CONTINUOUS BLOWER  
With the room thermostat switch set to ON, the supply air  
blower will operate continuously. The normally closed contact  
K5-1 provides 24 volt power to the M3 contactor. The M3-1, 2  
& 3 power contacts close and the blower motor operates.  
INTERMITTENT BLOWER  
With the room thermostat system switch set to the AUTO or  
HEAT position and the fan switch set to AUTO, the supply air  
blower will operate after the room thermostat calls for heat  
and the time delay relay closes.  
Gas flows into each of the second stage main burners and is  
ignited from the carryover tube flame.  
If IC2 fails to detect a pilot flame, it will continue to try for a  
maximum of 85 seconds to ignite the pilot tube. If the pilot  
flame is not detected, then IC2 will lock out first stage furnace  
operation until 24V power is removed from the module either  
at the unit or by resetting the room thermostat. Note that the  
second stage furnace can operate even if first stage has  
locked out.  
The TH1 closes, the heat relay RW1 is energized. The RW1-  
1 power contact closes energizing the line voltage draft  
motor. The RW1-2 contact is also closed. As the speed of the  
draft motor reaches approximately 2500 RPM, the centrifugal  
switch contact located on the end of the draft motor shaft  
closes to power the first stage ignition module IC1.  
When the heating cycle is complete, TH2 opens de-energiz-  
ing the RW2 then TH1 opens de-energizing RW1 and ETD,  
thus closing all gas valves. The blower motor will continue to  
run (approximately 45 seconds after the furnace is shut  
down) until ETD opens, de-energizing the K5 relay and M3  
contactor.  
REDUNDANT  
VALVE  
MAIN VALVE  
GAS MAIN  
SAFETY CONTROLS  
GAS  
VALVE  
TO MAIN  
BURNER  
The control circuit includes the following safety controls:  
TO PILOT BURNER  
1. Limit Control (LS). This control is located inside the heat  
exchanger compartment and is set to open at the tem-  
perature indicated in Table 16. It resets automatically.  
The limit switch operates when a high temperature con-  
dition, caused by inadequate supply air flow occurs, thus  
shutting down the ignition control and closing the main  
gas valves and energizing the blower.  
FIGURE 14 : GAS VALVE PIPING  
Ignition module IC1 will immediately start the first stage igni-  
tor sparking and will open the redundant valve located inside  
the first stage main gas valve GV1 to allow a flow of gas to  
only the first stage carryover tube. See Figure 14. Only after  
the pilot flame has been ignited and the presence of pilot  
flame detected at the IC1 by a signal sent back through the  
flame sensor is sparking terminated and the first stage main  
gas valve opened.  
2. Centrifugal Switch (CS). If the draft motor should fail, the  
centrifugal switch attached to the shaft of the motor pre-  
vents the ignition controls and gas valves from being  
energized.  
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TABLE 16: LIMIT CONTROL SETTING  
I
G
N
.
C
O
N
T
R
O
L
#
2
Capacity, MBH  
Units  
Limit  
Control  
Opens, °F  
(Tons)  
Input  
Output  
I
G
N
.
C
O
N
T
R
O
L
#
1
15 & 20  
15 & 20  
300  
400  
240  
320  
195  
195  
R
O
L
L
O
U
T
S
W
.
G
V
1
S
E
N
S
O
R
#
1
G
A
L
S
HEAT ANTICIPATOR SETPOINTS  
V
A
V
E
It is important that the anticipator setpoint be correct. Too  
high of a setting will result in longer heat cycles and a greater  
temperature swing in the conditioned space. Reducing the  
value below the correct setpoint will give shorter ON cycles  
and may result in the lowering of the temperature within the  
conditioned space.  
G
V
2
I
G
N
I
T
O
R
#
1
G
A
L
S
V
A
V
E
S
E
N
S
O
R
#
2
I
G
N
I
T
O
R
#
2
TABLE 17: HEAT ANTICIPATOR SETPOINT  
B
U
R
N
E
R
C
O
M
P
A
R
T
M
E
N
T
Gas Valve  
1st Stage  
2nd Stage  
FIGURE 15 : GAS VALVE AND CONTROLS  
Honeywell VR8440  
0.30 amp  
0.11 amp  
3. Redundant Gas Valve - There are two separate gas  
valves in the furnace. Each valve contains a main and a  
redundant valve. The redundant valves are located  
upstream of the main gas valves. Should either or both  
of the main gas valves fail in the open position the redun-  
dant valves serve as back-ups and shuts off the flow of  
gas.  
White-Rodgers 36C68  
START UP  
PRE-START CHECK LIST  
Complete the following checks before starting the unit.  
4. Flame Sensor Rod / 100% Ignition Control Lock-Out -  
The flame rods and controls are located per Figure 15. If  
an ignition control fails to detect a signal from the flame  
sensor indicating the pilot flame is properly ignited, then  
the main gas valve will not open. It will continue to try  
and ignite the pilot for a maximum of 85 seconds, then if  
the pilot flame is not detected, the ignition control will  
lock out furnace operation until 24V power is removed  
from the module either at the unit or by resetting the  
room thermostat.  
1. Check the type of gas being supplied. Be sure that it is  
the same as listed on the unit nameplate.  
2. Make sure that the vent and combustion air hoods have  
been properly installed.  
OPERATING INSTRUCTIONS  
5. Rollout Switch - This switch is located above the main  
burners in the control compartment which in the event of  
a sustained main burner rollout shuts off and locks out  
both ignition controls closing both gas valves. The igni-  
tion controls lock out furnace operation until 24V power  
is removed from the controls either at the unit or by  
resetting the room thermostat. Note the auto reset rollout  
switch must reset before allowing furnace operation.  
This furnace is equipped with an intermittent pilot  
and automatic re-ignition system. DO NOT attempt  
to manually light the pilot.  
TO LIGHT PILOT AND MAIN BURNERS:  
1. Turn off electric power to unit.  
6. Auxiliary limit switch (AUX) - This control is located  
inside the heat exchanger compartment and is set to  
open at 190F. It is a manual reset switch. If AUX limit  
trips, then the primary limit has not functioned correctly.  
Replace the primary limit switch.  
2. Turn room thermostat to lowest setting.  
3. Turn gas valve knob to on position.  
4. Turn on electric power to unit.  
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035-17233-000-C-0702  
5. Set room thermostat to desired temperature.(If thermo-  
stat set temperature is above room temperature, pilot  
burner ignition will occur and, after an interval to prove  
pilot flame, main burners will ignite).  
Adjust as follows:  
1. Remove the cap on the regulator. It's located next to the  
push-on electrical terminals.  
TO SHUT DOWN:  
2. To decrease the gas pressure, turn the adjusting screw  
counterclockwise.  
1. Turn off electric power to unit.  
2. Depress knob of gas valve while turning to off position.  
3. To increase the gas pressure, turn the adjusting screw  
clockwise.  
NOTE: The correct manifold pressure for these furnaces is  
3.5 IWG 0.3.  
POST-START CHECK LIST (GAS)  
After the entire control circuit has been energized and the  
heating section is operating, make the following checks:  
PILOT CHECKOUT  
1. Check for gas leaks in the unit piping as well as the sup-  
ply piping.  
The pilot flame should envelope the end of the flame sensor.  
Refer to Figure 16. To adjust pilot flame, (1) remove pilot  
adjustment cover screw, (2) increase or decrease the clear-  
ance for air to the desired level, (3) be sure to replace cover  
screw after adjustment to prevent possible gas leakage.  
2. Check for correct manifold gas pressures. See Checking  
Gas Input.  
3. Check the supply gas pressure. It must be within the lim-  
its shown on rating nameplate. Supply pressure should  
be checked with all gas appliances in the building at full  
fire. At no time should the standby gas line pressure  
exceed 13", nor the operating pressure drop below 5.0"  
for natural gas units. If gas pressure is outside these lim-  
its, contact the local gas utility for corrective action.  
Put the system into operation and observe through complete  
cycle to be sure all controls function properly.  
B
U
R
N
E
R
A
S
S
E
M
B
L
Y
B
R
A
C
K
E
T
F
L
A
M
E
S
E
N
S
O
R
B
U
L
B
MANIFOLD GAS PRESSURE ADJUSTMENT  
Small adjustments to the high-fire gas flow may be made by  
turning the pressure regulator adjusting screw on the auto-  
matic gas valve. Refer to Figure 16.  
1
T
/
8
"
G
A
P
B
E
T
W
E
E
N
C
A
R
R
Y
-
O
V
E
R
U
B
E
A
N
D
F
L
A
M
E
S
E
N
S
O
R
B
U
L
B
C
A
R
R
Y
-
O
V
E
R
T
U
B
E
On-Off Control  
High Fire Adj.  
FIGURE 17 : PROPER FLAME ADJUSTMENT  
BURNER INSTRUCTIONS  
(Under Screw)  
To check or change burners, pilot or orifices, CLOSE MAIN  
MANUAL SHUT-OFF VALVE AND SHUT OFF ALL ELEC-  
TRIC POWER TO THE UNIT.  
1. Remove the screws holding either end of the manifold to  
the burner supports.  
2. Open the union fitting in the gas supply line just  
upstream of the unit gas valve and downstream from the  
main manual shut-off valve.  
3. Remove the gas piping closure panel.  
Pilot Adj.  
(Under Screw)  
4. Disconnect wiring to the gas valves and spark ignitors.  
Remove the manifold-burner gas valve assembly by lift-  
ing up and pulling back.  
FIGURE 16 : TYPICAL GAS VALVE  
Burners are now accessible for service.  
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035-17233-000-C-0702  
Reverse the above procedure to replace the assemblies.  
Make sure that burners are level and seat at the rear of the  
heat exchanger.  
BURNER AIR SHUTTER ADJUSTMENT  
Adjust burner shutters so no yellow flame is observed in the  
heat exchanger tubes. Refer to Figure 17.  
CHECKING SUPPLY AIR CFM  
The RPM of the supply air blower will depend on the required  
CFM, the unit accessories or options and the static resis-  
tances of both the supply and the return air duct systems.  
With this information, the RPM for the supply air blower and  
the motor pulley adjustment (turns open) can be determined  
from the blower performance data in Tables 11 and 12.  
High speed drive accessories (containing a smaller blower  
pulley and a shorter belt) are available for applications requir-  
ing the supply air blower to produce higher CFM's and/or  
higher static pressures. Use Model 1LD0416 for 15 ton units  
and Model 1LD0417 for 20 ton units. Refer to Table 15 for  
blower motor and drive data.  
FIGURE 19 : BELT ADJUSTMENT  
2. Insert at least 8" of 1/4 inch tubing into each of these  
holes for sufficient penetration into the air flow on both  
sides of the indoor coil.  
NOTE: The tubes must be inserted and held in a position per-  
pendicular to the air flow so that velocity pressure will not  
affect the static pressure readings.  
FIGURE 18 : TYPICAL FLAME APPEARANCE  
3. Using an inclined manometer, determine the pressure  
drop across a dry evaporator coil. Since the moisture on  
an evaporator coil may vary greatly, measuring the pres-  
sure drop across a wet coil under field conditions would  
be inaccurate. To assure a dry coil, the compressors  
should be deactivated while the test is being run.  
Note the following:  
1. The supply air CFM must be within the limitations shown  
in Table 2.  
2. Pulleys can be adjusted in half turn increments.  
4. Knowing the pressure drop across a dry coil, the actual  
CFM through the unit and clean 2" filters, can be deter-  
mined from the curve in Figure 20.  
3. The tension on the belt should be adjusted as shown in  
Figure 19.  
Start the supply air blower motor. Adjust the resistances in  
both the supply and the return air duct systems to balance  
the air distribution throughout the conditioned space. The job  
specifications may require that this balancing be done by  
someone other than the equipment installer.  
After readings have been obtained, remove the tubes and  
reinstall the two 5/16" dot plugs that were removed in Step 1.  
To check the supply air CFM after the initial balancing has  
been completed:  
Failure to properly adjust the total system air quan-  
tity can result in extensive blower damage.  
1. Remove the two 5/16" dot plugs from the blower motor  
and the filter access panels shown in Figure 10.  
NOTE: De-energize the compressors before taking any test  
measurements to assure a dry indoor coil.  
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035-17233-000-C-0702  
2. With the furnace turned on, measure the time needed for  
one revolution of the hand on the smallest dial on the  
meter. A typical gas meter usually has a 1/2 or a 1 cubic  
foot test dial.  
3. Using the number of seconds for each revolution and the  
size of the test dial increment, find the cubic feet of gas  
consumed per hour from Table 18.  
If the actual input is not within 5% of the furnace rating (with  
allowance being made for the permissible range of the regu-  
lator setting), replace the orifice spuds with spuds of the  
proper size.  
NOTE: To find the Btu input, multiply the number of cubic feet  
of gas consumed per hour by the Btu content of the gas in  
your particular locality (contact your gas company for this  
information - it varies widely from city to city.)  
TABLE 18: GAS RATE - CUBIC FEET PER HOUR1  
FIGURE 20 : PRESSURE DROP ACROSS A DRY  
INDOOR COIL VS. SUPPLY AIR CFM  
SIZE OF TEST DIAL  
SECONDS FOR 1 REV.  
1/2 Cu. Ft.  
450  
300  
228  
180  
150  
129  
113  
100  
90  
1 Cu. Ft.  
900  
600  
450  
360  
300  
257  
225  
200  
180  
164  
150  
138  
129  
ADJUSTMENT OF TEMPERATURE RISE  
4
6
The temperature rise (or temperature difference between the  
return air and the heated air from the furnace) must lie within  
the range shown on the ETL rating plate and the data in Table  
2.  
8
10  
12  
14  
16  
18  
20  
22  
24  
26  
28  
After the temperature rise has been determined, the cfm can  
be calculated as follows:  
BtuhbInput × 0.8  
-------------------------------------------------------  
CFM =  
1.08 × °FbTempbRise  
82  
75  
After about 20 minutes of operation, determine the furnace  
temperature rise. Take readings of both the return air and the  
heated air in the ducts (about six feet from the furnace) where  
they will not be affected by radiant heat. Increase the blower  
cfm to decrease the temperature rise; decrease the blower  
cfm to increase the rise. Refer to Table 11 for blower motor  
and drive data.  
69  
64  
1
Example: By actual measurement, it takes 13 seconds  
for the hand on the 1-cubic foot dial to make a revolu-  
tion with just a 300,000 Btuh furnace running. Read  
across to the column in the table above, headed 1  
Cubic Foot, where you will see that 278 cubic feet of  
gas per hour are consumed by the furnace at that rate.  
Multiply 278 X 1050 (the Btu rating of the gas obtained  
from the local gas company). The result is 292,425  
Btuh, which is close to the 3000,000 Btuh rating of the  
furnace.  
BELT DRIVE BLOWER  
All units have belt drive single-speed blower motors. The vari-  
able pitch pulley on the blower motor can be adjusted to  
obtain the desired supply air CFM. Tighten belts enough to  
prevent slipping. but do not over tighten. Belt deflection  
should be between 1/4" and 1/2" per foot. Refer to Table 15  
for blower motor and drive data.  
SECURE OWNER’S APPROVAL  
CHECKING GAS INPUT  
NATURAL GAS  
When system is functioning properly, secure the owner’s  
approval. Show him the location of all disconnect switches  
and the thermostat. Teach him how to start and stop the unit  
and how to adjust temperature settings within the limitations  
of the system.  
1. Turn off all other gas appliances connected to the gas  
meter.  
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If desired, every three years remove both pipe plugs at each  
end shell and clean out any hardened grease or foreign mat-  
ter. Replace one plug on each end with a clean grease fitting.  
Using a low pressure grease gun, pump grease (Chevron  
SRI-2 or equivalent) into the bearing cavity until new grease  
shows at the open port. Do not over lubricate. Run the motor  
for ten minutes until excess grease is purged from the cavity.  
Replace the plugs.  
MAINTENANCE  
NORMAL MAINTENANCE  
Prior to any of the following maintenance proce-  
dures, shut off all electric power to the unit to pre-  
vent personal injury.  
On 20 ton only, units are supplied with blower shaft bearings  
that do not require maintenance but may be relubricated if  
desired. Every three years, using a low pressure grease gun,  
pump grease into the bearing grease fitting until grease just  
begins to show at the seals. Do not over lubricate. Use any  
lithium base grease recommended for ball bearing service.  
Periodic maintenance normally consists of changing or clean-  
ing filters and (under some conditions) cleaning the main  
burners  
OUTDOOR COIL  
FILTERS  
Dirt should not be allowed to accumulate on the outdoor coil  
surface or other parts in the air circuit. Cleaning should be as  
often as necessary to keep coil clean. Use a brush, vacuum  
cleaner attachment, or other suitable means. If water is used  
to clean coil, be sure electric power to the unit is shut off prior  
to cleaning.  
Inspect once a month. Replace disposable or clean perma-  
nent type as necessary. DO NOT replace permanent type  
with disposable. The dimensional size of the replacement fil-  
ter must be the same as the replaced filter.  
MOTORS  
NOTE: Exercise care when cleaning the coil so that the coil  
fins are not damaged.  
Outdoor fan motors are permanently lubricated and require  
no maintenance.  
NOTE: Do not permit the hot condenser air discharge to be  
obstructed by overhanging structures of shrubs.  
Ventor motor is factory lubricated for an estimated 10 year  
life.  
BURNER & PILOT  
Indoor Blower Motor and Drive - The indoor blower motor fea-  
tures ball bearings that do not require periodic lubrication.  
Periodic lubrication of the motor and bearings can extend the  
Periodically (at least annually at the beginning of each heat-  
ing season) make a visual check of the pilot and main burner  
flame. If necessary, adjust main burner primary air shutters to  
give a distinct, sharp blue flame as explained under BURNER  
AIR SHUTTER ADJUSTMENT. If it is not possible to adjust  
for the proper flame, the burners may need cleaning.  
life of components but is optional.  
TO CLEAN BURNERS  
Damage can occur if the bearings are overlubri-  
cated. Use grease sparingly.  
Remove them from the furnace as explained in Burner  
Instructions. Clean burners with hot water applied along top  
of the burner.  
COMBUSTION AIR DISCHARGE  
Perform all maintenance operations on the blower  
motor with electric power disconnected from the  
unit. Do not attempt to lubricate bearings with the  
unit in operation.  
Visually inspect discharge outlet periodically to make sure  
that the buildup of soot and dirt is not excessive. If necessary,  
clean to maintain adequate combustion air discharge.  
CLEANING FLUE PASSAGES AND HEATING ELE-  
MENTS  
On an annual basis, check the motor for accumulations of  
dust, etc. that may block the cooling slots in the motor shell.  
Check for loose, damaged or misaligned drive components.  
Check that all mounting bolts are tight. Replace defective  
parts as required.  
With proper combustion adjustment the heating element of a  
gas fired furnace will seldom need cleaning. If the element  
should become sooted, it can be cleaned as follows:  
Unitary Products  
25  
035-17233-000-C-0702  
1. Remove the burner assembly as outlined in BURNER  
INSTRUCTIONS.  
2. Remove the roof over the gas heat section.  
3. At the top plate from the top draft blower housing and the  
top draft blower wheel.  
4. Remove the screws holding the top of the flue collector  
box. Carefully remove the top of the flue collector box  
without ripping the adjacent insulation. Then remove the  
center divider plate separating the upper and lower flue  
boxes.  
5. On the inside of the flue collector box, remove the flue  
baffles from the tube interiors. Note the last bend of the  
baffle fits tightly against the tube forcing the end of the  
baffle to lock into the tube collar. This collar is formed  
when the tube is expanded into the end sheet. To  
FIGURE 21 : TYPICAL FLUE BAFFLE INSTALLA-  
TION  
TROUBLESHOOTING  
remove, move the end of the baffle toward the center of  
the tube releasing the end of the baffle from the tube col-  
lar, then pull straight out of the tube. Refer to Figure 20.  
6. Using a wire brush on a flexible wand, brush out the  
inside of each heat exchanger from the burner inlet and  
flue outlet ends.  
Label all wires prior to disconnection when servic-  
ing controls. Wiring errors can cause improper and  
dangerous operation. Verify proper operation after  
servicing.  
7. Brush out the inside of the flue collector box and the flue  
baffles.  
8. Run the wire brush down the vent hoods from the flue  
collector end.  
9. If soot build-up is particularly bad, remove the vent motor  
and clean the wheel and housings. Run the wire brush  
down the flue extensions at the outlet of the vent hous-  
ings.  
Troubleshooting of components necessarily  
requires opening the electrical control box with the  
power connected to the unit. Use extreme care  
when working with live circuits! Check the unit  
nameplate for the correct line voltage and set the  
volt meter to the correct range before making any  
connections with line terminals.  
10. After brushing is complete, blow all brushed areas with  
air or nitrogen. Vacuum as needed.  
11. Replace parts in the order they were removed in Steps 1  
through 4.  
Prior to any of the following maintenance proce-  
dures, shut off all electric power to the unit to pre-  
vent personal injury.  
12. When replacing the center and top of the flue collector  
box, be careful not to tear the adjoining insulation.  
NOTE: To find the Btu input, multiply the number of cubic feet  
of gas consumed per hour by the Btu content of the gas in  
your particular locality (contact your gas company for this  
information - it varies widely from city to city.)  
13. Ensure that all seams on the vent side of the combustion  
system are air tight. Apply a high temperature (+500°F)  
sealing compound where needed.  
26  
Unitary Products  
035-17233-000-C-0702  
1. The indoor blower motor is a non-inherently protected  
three-phase motor. Protection is provided by an overload  
relay for overcurrent and fuses for short circuit. If the  
motor fails to run, check the line voltage circuit and con-  
trol voltage circuit per the following procedure:  
has ignited with the fan switch in the AUTO position,  
check for loose 24 volt wiring between the relay  
board in the main control box, the Mate-N-Lok con-  
nector in the partition between the evaporator and  
gas heat sections and the time delay relay (ETD).  
a. If the Indoor Blower Motor does not operate, check  
visually that contactor M3 is pulled in. If so, check  
for line voltage between all three phases at the line  
terminals of the Blower Overload Relay (BOR). If  
line voltage is found, check the leads to the blower  
motor for open circuit. If line voltage is found at the  
motor leads (inside the conduit box on the motor  
shell), disconnect the motor and check for open  
windings per the motor wiring diagram. If open wind-  
ings are found, replace the motor. If line voltage is  
not found at the BOR, trace the leads back to the  
field supply terminal block, checking for an open cir-  
cuit or blown fuses.  
g. If all control wiring is fine, check for 24 volts at the  
relay board. If 24 volts is present, replace the relay  
board. If 24 volts is not present, replace the (ETD)  
relay.  
NOTE: The furnace may shut itself down on a high tempera-  
ture condition during the procedure, but this will not effect the  
test if it is done within 5 minutes of furnace shut-down.  
3. The supply air blower operates but the draft motor does  
not when the room thermostat is set to call for heat and  
the fan switch in the ON position.  
a. The draft motor has inherent protection. If the motor  
shell is hot to the touch, wait for the internal over-  
load to reset.  
b. If the contactor M3 is not pulled in, check for control  
voltage (24V) at the M3 coil. If voltage is found,  
replace the contactor. If control voltage is not found  
at M3, check for voltage across terminals 95 & 96 of  
the BOR. If voltage exists, the BOR is open on over-  
load. The BOR should be set to the auto reset posi-  
tion. The BOR must cool down in order to reset. If  
the BOR will not reset, replace the BOR. If the BOR  
resets and M3 pulls in, but the indoor blower motor  
will still not run, refer to para. (a) for troubleshooting  
the line voltage supply circuit. If control voltage is  
not found at the BOR, trace the circuit back to the  
relay board and thermostat per the unit wiring dia-  
gram. Replace any defective components.  
b. If the motor shell is cold with the room thermostat  
calling for heat, check for line voltage at the motor's  
Mate-N-Lok connector attached to the evaporator  
partition. If line voltage is present, replace the draft  
motor.  
c. If line voltage is not present, check for line voltage at  
the heat relay (RW1) contacts in the main control  
box and check to see if the (RW1) is pulled in.  
d. If the (RW1) relay is pulled in, check for a loose line  
voltage connection.  
e. If the (RW1) relay is not pulled in, check for 24 volts  
at the (RW1) coil. If 24 volts is present, replace the  
(RW1) relay. If 24 volts is not present, check for a  
loose 24 volt connection back to the relay board and  
check the connections from the room thermostat to  
the relay board. If all connections are correct,  
replace the relay board.  
2. Draft motor operates and furnace lights but supply air  
blower does not start after a short time delay with room  
thermostat fan switch set to AUTO.  
a. Set fan switch to ON. If blower motor runs, go to  
Step f. If it does not, check to see if line voltage is  
being supplied to the contacts of the contactor (M3),  
and if the contactor is pulled in. Check for loose wir-  
ing.  
4. The draft motor runs but the furnace does not light and  
the sparker does not spark.  
b. If contactor (M3) is pulled in, proceed with the trou-  
bleshooting steps indicated in Step 1 above.  
a. The ignition control (IC1, IC2) may be locked out  
due to either a flame roll out or 100% shut off. These  
safety features are described above. If lock-out has  
occurred, 24V must be removed from the ignition  
controls. This is done at the unit or by resetting the  
room thermostat. After resetting 24V, check for  
proper furnace operation. If lock-out continues to  
occur, locate the source of the problem and correct.  
c. If (M3) is pulled in and the blower motor still does  
not run, replace the blower motor.  
d. If (M3) is not pulled in, check for 24 volts at the (M3)  
coil. If 24 volts is present, replace the (M3) contac-  
tor.  
e. If 24 volts is not present at the (M3) coil, check for  
loose 24 volt wiring back to the relay board. Check  
control wiring to the room thermostat. If all is fine,  
replace the relay board.  
b. Check all 24 volt connections from the relay board  
to and in the gas heat section. Check low voltage  
connections to the (ETD) located in the control box.  
c. If the furnace is hot, it may be out on an over-tem-  
perature condition, wait for limit reset.  
f. If the blower motor runs with the fan switch in the  
ON position but does not run soon after the furnace  
Unitary Products  
27  
d. If the furnace is cold, check for 24 volts at wire 241  
attached to the time delay relay (ETD) located in the  
main control box. If 24 volts is not found, replace the  
ETD relay.  
6. The sparker sparks at the pilot burner but the pilot does  
not ignite and a gas odor is detected at the draft motor  
outlet.  
a. Adjust the pilot adjust screw on the gas valve as  
described in PILOT CHECKOUT.  
e. If 24 volts is found at wire 241, remove the wires  
attached to the (ETD) and with a VOM, check for  
continuity across contacts 1 and 2. If none is found,  
the (ETD) is open and must be replaced. If there is  
continuity, re-attach the wires.With the draft motor  
running, check for 24 volts at terminal 4 of (RW1-2)  
and (RW2-1). If 24 volts is not present, the centrifu-  
gal switch (CS) has not closed or has gone bad.  
Check the line voltage to the unit - if it is correct,  
replace the draft motor. If line voltage is low, call the  
power company.  
b. Check the supply pressure as described in POST  
START CHECK LIST. Make adjustments as neces-  
sary.  
c. Check the pilot orifice for obstruction as described in  
para. 5d. Clean as needed but the problem should  
not be the gas valve.  
7. The pilot burner ignites but the sparker continues to  
spark and the main burners do not ignite.  
a. Make the same checks and adjustment as  
described in para. 6.  
f. Check for 24V at terminal 2 of (RW1-2 and RW2-1).  
If 24V is not present, check for 24V at (RW1 and  
RW2) relay coils. If these relays are pulled in, then  
check for a loose connection at terminal 2 and termi-  
nal 4 of each relay. If no problem is found, then  
replace (RW1 and/or RW2) as required.  
b. Make sure that the pilot burner is not bent or dam-  
aged.  
c. Make sure that the ground connections at the pilot  
burner, gas valve and ignitor control are intact.  
Check the high tension wire for good electrical con-  
nection. If all are intact, replace the ignitor module.  
g. If 24 volts is present at the ignitor controls, check all  
control wiring at the ignitor controls and the high ten-  
sion wire to the ignitors. Check that the ground wires  
from the ignitor controls, the gas valves and pilot  
burners are all intact and making good electrical  
connection. Check to make sure that the ceramic  
insulator on the pilot ignitors or sensors is not bro-  
ken or cracked, if all are intact, replace the ignition  
control IC1 or IC2.  
8. The pilot burner lights and the spark stops but the main  
burners do not light.  
a. Check electrical connections between the ignitor  
control and the gas valve. If intact, check for 24 volts  
across terminals MV and COMMON terminals. If no  
voltage detected, replace ignitor control. If voltage is  
present, replace gas valve.  
5. The draft motor runs and the sparker sparks at the pilot  
burner but the pilot does not ignite and a gas odor is not  
detected at the draft motor outlet.  
9. Furnace lights with roll-out or one burner has delayed  
ignition.  
a. Check to make sure gas is being supplied to the  
unit. Make sure that the gas pressure to the unit is  
within the proper limits as described in the POST  
START CHECK LIST and that the pilot adjust screw  
is allowing some flow of gas as described in PILOT  
CHECKOUT.  
a. Make sure that the pilot burner is aligned properly  
with the carryover as described in PILOT CHECK-  
OUT.  
b. Make sure that the carry overs on adjoining burners  
are screwed fast and are level with respect to one  
another.  
b. Check all wiring between the ignitor control and the  
gas valve. Check to make sure the ground connec-  
tions are intact.  
10. Main burners light but exhibit erratic flame characteris-  
tics.  
c. If the wiring is intact, check for 24 volts across termi-  
nals PV and COMMON on the ignitor control. If 24  
volts is not present, replace the ignitor control.  
a. Adjust air shutters as described in BURNER AIR  
SHUTTER ADJUSTMENT.  
b. Check the main burner orifices for obstruction and  
alignment. Removal procedure is described in  
BURNER INSTRUCTIONS. Clean or replace burner  
orifices and burners as needed.  
d. If 24 volts is present, remove the pilot burner and  
remove the pilot orifice from the pilot burner. The ori-  
fice is removed in the direction opposite the flow of  
gas. Inspect the orifice for obstruction. If it is clear,  
replace the main gas valve.  
Subject to change without notice. Printed in U.S.A.  
Copyright © by Unitary Products 2002. All rights reserved.  
Supersedes: 035-17233-000 Rev B (0500)  
035-17233-000-C-0702  
Unitary  
Products  
Group  
5005  
York  
Drive  
Norman  
OK  
73069  

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