Weil McLain Boiler 550 110 260 02002 User Manual

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GOLD CGs Gas-Fired Water Boiler

Contents

How it works.................................................................. 2–3

Hazard definitions.............................................................. 4

Please read before proceeding......................................... 5

1. Prepare boiler location ............................................ 6–11

2. Prepare boiler......................................................... 12–13

3. Water piping........................................................... 14–23

4. Venting & combustion air............................................ 24

5. Gas piping .............................................................. 24–25

6. Field wiring................................................................... 26

7. Start-up .................................................................. 27–29

8. Check-out procedure................................................... 30

9. Operation ............................................................... 31–34

10. Service and maintenance.................................... 35–40

11. Troubleshooting .................................................. 41–51

12. Replacement parts............................................... 52–57

13. Dimensions and ratings ...................................... 58–59

Hazard definitions

The following defined terms are used throughout this manual to bring attention to the presence of hazards of

various risk levels or to important information concerning the life of the product.

Indicates presence of hazards that will cause severe personal injury, death or substantial

property damage.

Indicates presence of hazards that can cause severe personal injury, death or substantial

property damage.

Indicates presence of hazards that will or can cause minor personal injury or property damage.

Indicates special instructions on installation, operation or maintenance that are important

but not related to personal injury or property damage.

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Please read before proceeding

Installer

User

Read all instructions before

installing. Follow all instructions in

proper order to prevent personal

injury or death.

•

This manual is for use only by your qualified

heating installer/service technician.

Please refer to the User’s Information Manual for

your reference.

We recommend regular service by a qualified

service technician, at least annually.

•

Also refer to CGs Venting Supplements.

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.

When calling or writing about the boiler— Please have the boiler model number from the

boiler rating label and the CP number from the boiler jacket. You may list the CP number in

the space provided on the Installation and service certificate found on page 30.

Failure to adhere to the guidelines on this page can result in severe personal injury, death

or substantial property damage.

•

Continual fresh makeup water will reduce boiler

life. Mineral buildup in sections reduces heat

transfer, overheats cast iron, and causes section

failure. Addition of oxygen and other gases can

cause internal corrosion. Leaks in boiler or piping

must be repaired at once to prevent makeup

water.

When servicing boiler —

•

To avoid electric shock, disconnect electrical

supply before performing maintenance.

To avoid severe burns, allow boiler to cool before

performing maintenance.

•

Boiler operation —

Do not add cold water to hot boiler. Thermal

shock can cause sections to crack.

•

Do not block flow of combustion or ventilation

air to 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 Glycol — potential fire hazard —

supply at a location external to the appliance.

All glycol is flammable when exposed to high

•

Do not use this boiler if any part has been under

temperatures. If glycol is allowed to accumulate in

water. Immediately call a qualified service

or around the boiler or any other potential ignition

technician to inspect the boiler and to replace any

source, a fire can develop. In order to prevent

part of the control system and any gas control

potential severe personal injury, death or substantial

that has been under water.

property damage from fire and/or structural damage:

•

Never store glycol of any kind near the boiler or

any potential ignition source.

Monitor and inspect the system and boiler

regularly for leakage. Repair any leaks

immediately to prevent possible accumulation

of glycol.

Boiler water —

•

Do not use petroleum-based cleaning or sealing

compounds in boiler system. Water seal

deterioration will occur, causing leakage between

sections. This can result in substantial property

damage.

•

Never use automotive antifreeze or ethylene

glycol in the system. Using these glycols can lead

to hazardous leakage of glycol in the boiler

system.

•

Do not use "homemade cures" or "boiler patent

medicines". Serious damage to boiler, personnel

and/or property may result.

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GOLD CGs Gas-Fired Water Boiler

Prepare boiler location — codes & checklist

Installations must

•

Local, state, provincial, and national codes, laws, regulations and

ordinances.

follow these codes:

•

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.

•

National Electrical Code.

For Canada only: B149.1 or B149.2 Installation Code, CSA C22.1

Canadian Electrical Code Part 1 and any local codes.

The CGs boiler gas manifold and controls met safe

lighting and other performance criteria when boiler

underwent tests specified in ANSI Z21.13 — latest

edition.

Before locating the boiler,

check the following:

•

Check for nearby connection to:

•

System water piping

Venting connections

Gas supply piping

Electrical power

Check area around boiler. Remove any combustible materials, gasoline

and other flammable liquids.

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.

•

Boiler must be installed so that gas control system components are

protected from dripping or spraying water or rain during operation

or service.

If new boiler will replace existing boiler, check for and correct system

problems, such as:

1. System leaks causing oxygen corrosion or section cracks from

hard water deposits.

2. Incorrectly-sized expansion tank.

3. Lack of antifreeze in boiler water causing system and boiler to

freeze and leak.

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Prepare boiler location — clearances

Provide the following clearances: Flooring and foundation

Flooring

1. Hot water pipes — at least ½" from combustible

materials.

The CGs boiler is approved for installation on

combustible flooring, but must never be installed on

carpeting.

2. Recommended service clearances — See Figure 1.

3. Minimum clearances for tight spaces — See

Figure 2.

Do not install boiler on carpeting

even if foundation is used. Fire can

result, causing severe personal

injury, death or substantial property

damage.

Figure 1 Recommended clearances for service

Foundation

Provide a solid brick or minimum 2-inch thick

concrete foundation pad if any of the following is true:

•

floor can become flooded.

the boiler mounting area is not level.

The minimum foundation size is 25" long by:

Boiler model number

CGs-3

Width — Inches

Figure 2 Minimum clearances for tight spaces

CGs-4

CGs-5

CGs-6

Residential garage installation

Precautions

Take the following special precautions when installing

the boiler in a residential garage. If the boiler is located

in a residential garage, per ANSI Z223.1, paragraph

5.1.9:

•

Mount the boiler a minimum of 18 inches

above the floor of the garage to assure the

burner and ignition devices will be no less

than 18 inches above the floor.

•

Locate or protect the boiler so it cannot be

damaged by a moving vehicle.

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Prepare boiler location — vent system

appliance to their previous conditions of use.

Removing from existing vent

Any improper operation of common venting system

Do not install the CGs into a

common vent with any other

appliance. This will cause flue gas

spillage or appliance malfunction,

should be corrected so the installation conforms with

the National Fuel Gas Code, ANSI Z223.1 — latest

edition. Correct by resizing to approach the minimum

size as determined using the appropriate tables in Part

resulting in possible severe personal 11 of that code. Canadian installations must comply

injury, death or substantial property

damage.

with B149.1 or B149.2 Installation Code.

Failure to follow all instructions can

result in flue gas spillage and carbon

monoxide emissions, causing

severe personal injury or death.

CGs special vent system

Ventsystem

The CGs boiler requires a special vent system, designed

for pressurized venting. Model CGs-3 is rated ANSI

Z21.13 Category IV (pressurized vent, likely to

condense in the vent). Models CGs-4, -5 and -6 are rated

Z21.13 Category III (pressurized vent).

Whenremovingboilerfromexisting

commonventsystem:

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.

You may use any of the vent systems covered by the

CGs Venting Supplements included in the envelope

assembly. The CGs vent starter is a special item, designed

only for the CGs boiler, available from each vendor.

Do not attempt to connect the vent to the CGs boiler

with any other means.

a. Seal any unused openings in the common venting

DO NOT mix components from

different systems. The vent system

could fail, causing leakage of flue

products into the living space.

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.

Ventterminationand

combustionairsupply

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.

The CGs boiler may be vented through the roof or

through a side wall. Follow the appropriate vent

supplement for the vent system chosen. The maximum

vent length depends on boiler size. Refer to the vent

supplement to determine acceptable vent length.

Combustion air for the CGs boiler may be from inside

or ducted directly to the boiler from outside. For

outside air (direct vent installation), two options are

available for the flue/air termination. The air supply

must ALWAYS terminate at the same location as the

d. Place in operation the appliance being inspected. flue, using either:

Follow the lighting instructions. Adjust thermostat

so appliance will operate continuously.

1. Vertical direct vent installation. Obtain the Weil-

McLain Through-Roof or Through-Unused

Chimney termination kit and supplement. Refer to

Vertical DirectVentingVenting Supplement,packed

with the kit, and to the vent manufacturer’s

instructions for the vent material chosen.

e. Test for spillage at 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 2. Sidewall direct vent installation. Use the Vent/Air

remaining connected to the common venting

system properly vents when tested as outlined

above, return doors, windows, exhaust fans,

fireplace dampers, and any other gas-burning

Intake termination kit shipped with the boiler.

Refer to CGs Direct Venting: Sidewall & Direct

Exhaust Venting: Vertical or Sidewall Venting

Supplement shipped with the boiler.

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Prepare boiler location — contamination

Air contamination

Refer to Table 1 for products and areas which may cause

contaminated combustion air.

Please review the following information on potential

combustion air contamination problems.

If the boiler is installed in any area likely to cause contamination, or if products which

would contaminate the air cannot be removed, you must pipe combustion air to the boiler

air intake. Contaminated combustion air will damage the boiler, resulting in possible severe

personal injury, death or substantial property damage. Do not install CGs boiler in a laundry

room or pool facility, for example, without using ducted outside air. These areas will always

contain contaminants.

Table 1 Corrosive contaminants

Products to avoid

Areas likely to have contaminants

Spray cans containing chloro/fluorocarbons

Permanent wave solutions

Dry cleaning/laundry areas and establishments

Swimming pools

Chlorinated waxes/cleaners

Metal fabrication plants

Beauty shops

Chlorine-based swimming pool chemicals

Calcium chloride used for thawing

Sodium chloride used for water softening

Refrigerant leaks

Refrigeration repair shops

Photo processing plants

Auto body shops

Paint or varnish removers

Plastic manufacturing plants

Furniture refinishing areas and establishments

New building construction

Remodeling areas

Hydrochloric acid/muriatic acid

Cements and glues

Antistatic fabric softeners used in clothes dryers

Chlorine-type bleaches, detergents, and cleaning

solvents found in household laundry rooms

Garages with workshops

Adhesives used to fasten building products and

other similar products

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Prepare boiler location — air openings

CGs combustion air options

Louverallowance

Using inside air — direct exhaust vent

The free area of openings means the area after

reduction for any installed louvers or grilles. Be sure

The CGs boiler can use inside air if no contaminants to consider this reduction when sizing the air openings.

are present in the boiler space. If contaminants are likely

to be present, install the CGs boiler as a direct vent

appliance, using the appropriate vent supplement and

the instructions in this manual.

Special considerations

Using outside air — direct vent

Tightconstruction

Combustion air can be ducted directly from outside

to the CGs boiler air intake fitting. This method is

ANSI Z223.1 defines unusually tight construction

where:

defined as direct vent (also referred to as sealed

combustion). Refer to the appropriate vent supplement

and the instructions in this manual. Two options are

a. Walls and ceilings exposed to the outside

available: sidewall or vertical direct vent. Each requires

atmosphere have a continuous water vapor retarder

a special vent component kit.

with a rating of 1 perm or less with openings

gasketed, and . . .

b. Weather-stripping has been added on openable

windows and doors, and . . .

c. Caulking or sealants are applied to areas such as

joints around windows and door frames, between

sole plates and floors, between wall-ceiling joints,

Sizing air openings

between wall panels, at penetrations for plumbing,

electrical, and gas lines, and in other openings.

Air openings provide for ventilation (as well as

combustion air) to prevent overheating of the boiler

controls and boiler space. Air is also needed for other

appliances located in the same space.

For buildings with such construction, provide air

openings into the building from outside, sized per the

appropriate case in Figure 3 if appliances are to use

inside air for combustion and ventilation.

Use Figure 3, selecting the appropriate installation

conditions. Note that the sizing given in Figure 3

applies only to CGs installations with clearances no

smaller than shown in Figure 1, page 7 of this manual.

For smaller clearances, regardless of how the air

openings are arranged, two openings providing free

area of 1 square inch per 1,000 Btuh input of all

appliances in the space are required.

Exhaust fans and air movers

The appliance space must never be under a negative

pressure unless all appliances are installed as direct vent.

Always provide air openings sized not only to the

dimensions required for the firing rate of all appliances,

but also to handle the air movement rate of the exhaust

fans or air movers using air from the building or space.

Air openings must be sized to

handle all appliances and air

movers (exhaust fans, etc.) using the

air supply.

Motorizedairdampers

The sizing given in Figure 3 is based on the National

Fuel Gas Code, ANSI Z223.1, allowing adequate air

opening for gravity-vented gas appliances (Category I).

The CGs boiler is rated Category III or IV (pressurized

vent), and has different requirements for combustion

and ventilation air, reflected by the special sizing

instructions given in Figure 3. The air openings

recommended in Figure 3 will allow adequate

ventilation and combustion air provided the boiler

room is not subjected to negative pressure due to

exhaust fans or other mechanical ventilation devices.

Refer to the National Fuel Gas Code for dealing with

other conditions.

If the air openings are fitted with motorized dampers,

electrically interlock the damper to:

•

Prevent the boiler from firing if the damper is not

fully open.

Shut the boiler down should the damper close

during boiler operation.

To accomplish this interlock, wire an isolated contact

(proving the damper open) in series with the

thermostat input to the boiler. The boiler will not start

if this contact is open, and will shut down should it

open during operation.

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Figure 3 Sizing air openings for CGs installations

Room Air Openings

Required area of the air openings given in this

table are free area — after the correction for

louver obstruction. (See Exception below.)

Direct exhaust vent installation

Direct vent installation

(CGs using room air for combustion)

(combustion air piped to CGs)

Combustion

air piping

Combustion

air piping

Apply this table only to installations with

clearances no smaller than those shown in

Figure 1, page 7 of this manual.

Other

appliances

Other

appliances

CGs

For installations with clearances less than

shown in Figure 1, page 7 of this manual,

provide 2 openings, each with 1 square inch

of free area per 1,000 Btuh of total input of

all appliances.

Room shared

with other appliances

Room shared

with other appliances

CGs alone

in room

CGs alone

in room

2 Openings —

each opening:

2 Openings —

each opening:

2 Openings —

each opening:

NO Openings are

needed, provided:

12”

Max

A Air from Inside

Air

opening

1 square inch

free area per

Clearance around

boiler is NO LESS

than shown in

Figure 1, page 7

of this manual.

1,000 Btuh input of

other appliances

plus CGs

4,000 Btuh input

of CGs

1,000 Btuh input of

other appliances

only (not CGs)

Air

opening

CGs

12”

Max

2 Openings —

each opening:

2 Openings —

each opening:

2 Openings —

each opening:

NO Openings are

needed, provided:

12”

Max

B Air Directly

from Outside

Air

opening

1 square inch

free area per

Clearance around

boiler is NO LESS

than shown in

Air

4,000 Btuh input of

other appliances

plus CGs

4,000 Btuh input

of CGs

4,000 Btuh input of

other appliances

only (not CGs)

opening

CGs

12”

Figure 1, page 7

of this manual.

Max

Duct

2 Openings —

each opening:

2 Openings —

each opening:

2 Openings —

each opening:

NO Openings are

needed, provided:

12”

C Air from Outside

Through horizontal

ducts

Max

Air

opening

1 square inch

free area per

Clearance around

boiler is NO LESS

than shown in

Figure 1, page 7

of this manual.

2,000 Btuh input of

other appliances

plus CGs

4,000 Btuh input

of CGs

2,000 Btuh input of

other appliances

only (not CGs)

Air

opening

CGs

12”

Max

Outside or ventilated attic

2 Openings —

each opening:

2 Openings —

each opening:

2 Openings —

each opening:

NO Openings are

needed, provided:

D Air from Outside or Attic —

Lower Opening in Floor

or Vertical Duct

Duct

1 square inch

free area per

Clearance around

boiler is NO LESS

than shown in

Figure 1, page 7

of this manual.

CGs

12”

Max

4,000 Btuh input of

other appliances

plus CGs

4,000 Btuh input

of CGs

4,000 Btuh input of

other appliances

only (not CGs)

Ventilated

crawl space

26007

NOcombustion air openings are needed when the boiler (and other appliances) are installed in a space with a volume

NO LESS than 50 cubic feet per 1,000 Btuh of all installed appliances. Sum the total input of all appliances in MBH

(1,000'sofBtuh) andmultiply thisnumber times 50. Building must notbeof Tightconstruction(seepage10).

Exception to

combustion air

opening rules:

Example: For total input of 100 MBH (100,000 Btuh), minimum volume is 50 x 100 = 5,000 cubic feet. At a ceiling

height of8feet, spacemust haveatleast5,000 ÷ 8 =625square feet(25feetx25feet, forinstance).

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Prepare boiler — placement & setup

Place boiler/crate near position

death or substantial property

damage.

1. Leave boiler in crate and on pallet until installation

site is ready.

3. Reinstall inlet air box top panel.

Inlet air box top panel must be in

2. Move entire crate and pallet next to selected

location.

position during boiler operation.

Failure to do so could result in

severe personal injury, death or

substantial property damage.

3. Remove crate.

4. Remove boiler from pallet.

Do not drop boiler or bump jacket

on floor or pallet. Damage to boiler

can result.

Orifice replacement procedure

(when required)

1. Remove the screws securing the inlet air box top

panel.

a. Tilt left side of boiler up and place a board

under left legs.

2. Remove inlet air box top panel and inspect the fiber

gasket. Verify the gasket is in good condition and

can seal around the complete perimeter of the air

box. Replace the gasket if necessary.

b. Tilt boiler the other way and place a board

under right legs.

c. Slide boiler backward off pallet and into

position.

3. Using a /₁₆" open-end wrench, remove the burner

orifices from the manifold.

5. Check level.

4. Apply a small amount of pipe dope to each of the

new orifices and install in the manifold using a ⁷/₁₆"

open-end wrench. Make sure the orifices are aligned

correctly, not cross-threaded in the manifold

tappings.

a. Shim legs, if necessary.

b. Do not alter legs.

Use only pipe dope compatible with

propane gas, even if boiler is to be

operated on natural gas. Failure to

comply could result in severe

personal injury, death or substantial

property damage.

Inspect orifices and burners

1. Remove front jacket door. Remove inlet air box

top panel (see Figure 27, item 13, page 54).

2. Check for correctly-sized manifold orifices. See 5. Carefully replace the inlet air box top panel, making

Table 2 for sizing. (The orifice size is stamped on

the orifice spud barrel.)

sure the gasket is in place will seal all around the

perimeter.

Correctly-sized manifold orifices 6. Follow the check-out procedure, section 8 page 30,

must be used. Failure to do so will

result in severe personal injury,

to assure the boiler is now operating properly after

orifices are replaced.

Table 2 Manifold orifice sizing

Location

U. S.

Natural gas

Propane gas

0-2,000 ft

over 2,000 ft

(Note 1)

0-2,000 ft

1.65 mm

0-2,000 ft

1.65 mm

over 2,000 ft

(Note 1)

2.70 mm

0-2,000 ft

2.70 mm

2,000-4,500

#38

2,000-4,500

#53

Canada

Note 1: For elevations above 2,000 feet, contact your local Weil-McLain sales office for details.

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Prepare boiler — pressure test

Perform hydrostatic pressure test

Pressure test boiler before attaching water or gas piping (except as noted below) or electrical

supply.

Prepare boiler for test

1. Remove the shipping nipple (from CGs supply tapping) and remove the boiler relief

valve. Temporarily plug the relief valve tapping with a ¾" NPT pipe plug.

2. Remove 1¼" nipple, reducing tee and drain valve from accessory bag. Install in boiler

return connection as shown on page 3 and Figure 29, page 56. Install circulator on either

the return or supply.

3. Remove 1¼" nipple, 1¼" tee, bushing and pressure/temperature gauge from accessory

bag. Pipe to boiler supply connection as shown on page 3 and Figure 29, page 56. (Use

pipe dope sparingly.)

4. Connect a hose to boiler drain valve, the other end connected to a fresh water supply.

Make sure hose can also be used to drain boiler after test.

5. Connect a nipple and shutoff valve to system supply connection on the 1¼" tee. This

valve will be used to bleed air during the fill. (Valve and nipple are not included with

boiler.)

6. Connect a nipple and shutoff valve to system return connection (at circulator flange if

circulator installed on return). This valve will be used to bleed air during the fill. (Valve

and nipple are not included with boiler.)

Fill and pressure test

1. Open the shutoff valves you installed on supply and return connections.

2. Slowly open boiler drain valve and fresh water supply to fill boiler with water.

3. When water flows from shutoff valves, close boiler drain valve.

4. Close shutoff valves.

5. Slowly reopen boiler drain valve until test pressure on the pressure/temperature gauge

reaches no more than:

•

45 psig for boilers with 30 psig relief valve.

75 psig for boilers with 50 psig relief valve.

6. Test for no more than 10 minutes at:

•

45 psig for boilers with 30 psig relief valve.

75 psig for boilers with 50 psig relief valve.

Do not leave boiler unattended. A cold water fill could expand and cause

excessive pressure, resulting in severe personal injury, death or substantial

property damage.

7. Make sure constant gauge pressure has been maintained throughout test. Check for leaks.

Repair if found.

Leaks must be repaired at once. Failure to do so can damage boiler,

resulting in substantial property damage.

Do not use petroleum-based cleaning or sealing compounds in boiler

system. Severe damage to boiler will occur, resulting in substantial property

damage.

Drain and remove fittings

1. Disconnect fill water hose from water source.

2. Drain boiler at drain valve or out hose, whichever provides best access to drain. Remove

hose after draining if used to drain boiler.

3. Remove nipples and valves unless they will remain for use in the system piping.

4. Remove plug from relief valve tapping. See section 3a to replace relief valve.

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Water piping — general information

General piping information

Circulator

If installation is to comply with ASME or Canadian requirements, an

additional high temperature limit is needed. Install control in supply

piping between boiler and isolation valve. Set second control to minimum

20 °F above setpoint of first control. Maximum allowable setpoint is 240 °F.

See section 9b, page 32 for wiring.

The circulator is shipped loose (wiring pre-attached

to boiler) to allow you to locate it either in the return

or supply piping, as desired. See page 3 for a typical

installation. Pipe the expansion tank to the suction side

of the circulator whenever possible. Install an air

separator in the supply piping. Connect the expansion

tank to the air separator only if the separator is on the

suction side of the circulator. Always install the system

fill connection at the same point as the expansion tank

connection to the system. Figures 4 and 5 show typical

near-boiler piping connections.

A low water cutoff device is required when boiler is installed above

radiation level or by certain state or local codes or insurance companies.

Use low water cutoff designed for water installations. Electrode probe-

type is recommended. Purchase and install in tee in supply piping above

boiler.

Use backflow check valve in cold water supply as required by local codes.

System water piping

Pressure/temperature gauge

See Figure 4 (diaphragm-type or bladder-type

expansion tank) or Figure 5 (closed-type expansion

tank) on page 15, and Table 3 below, for near-boiler

and single-zone systems designed for return water at

least 130 °F.

Install pressure/temperature gauge in tee on supply piping (as shown in

drawing on page 3). The gauge well is a self-closing valve, allowing removal

of the gauge without draining the system.

Slowly remove pressure/temperature gauge from well.

The self-closing valve could leak if clogged with

sediment. If water begins to spray, stop removing gauge.

Close system fill valve and drain enough water to release

system pressure before continuing with gauge removal.

Escaping hot water could cause severe personal injury.

See pages 16-17 to complete multiple-zone piping or

pages 18-23 to complete piping for radiant heating

systems or converted gravity systems.

Refer to page 23 for boilers used with refrigeration systems.

Table 3 Water pipe size (based on 20 °F rise)

Relief valve

Install relief valve vertically in ¾" tapping on side of boiler. See Figure 4

or 5 and the tag attached to the relief valve for manufacturer’s instructions.

Boiler

model

system

From

system

number

To avoid water damage or scalding due to relief valve

operation:

CGs-3

CGs-4

CGs-5

CGs-6

•

Discharge line must be connected to relief valve outlet and run to a

safe place of disposal. Terminate the discharge line to eliminate

possibility of severe burns should the valve discharge.

1 ¼"

•

Discharge line must be as short as possible and be the same size as

the valve discharge connection throughout its entire length.

Note: Circulator flange supplied with boiler is same size as

recommended piping above.

Discharge line must pitch downward from the valve and terminate at

least 6" above the floor drain where any discharge will be clearly visible.

Install boiler such that —

The discharge line shall terminate plain, not threaded, with a material

serviceable for temperatures of 375 °F or greater.

•

Chilled medium, if used, is piped in parallel with

heating boiler. Use appropriate valves to prevent

chilled medium from entering boiler. Consult

I=B=R Installation and Piping Guides.

•

Do not pipe the discharge to any place where freezing could occur.

No shutoff valve shall be installed between the relief valve and boiler,

or in the discharge line. Do not plug or place any obstruction in the

discharge line.

If boiler is connected to heating coils located in air

handling units where they can be exposed to

refrigerated air, use flow control valves or other

automatic means to prevent gravity circulation

during cooling cycle. Circulation of cold water

through the boiler could result in damage to the

heat exchanger, causing possible severe personal

injury, death or substantial property damage.

•

Failure to comply with the above guidelines could result in failure of

the relief valve to operate, resulting in possibility of severe personal

injury, death or substantial property damage.

Test the operation of the valve after filling and pressurizing system

by lifting the lever. Make sure the valve discharges freely. If the valve

fails to operate correctly, replace it with a new relief valve.

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Boiler Manual

Water piping — single-zone system

Expansion tank

Closed-type expansion tank —

Diaphragm-typeorbladder-type

expansion tank — Figure 4

Figure 5

1. Ensure expansion tank size will handle boiler and

system water volume and temperature. See tank

manufacturer’s instructions for details.

1. Ensure expansion tank size will handle boiler and

system water volume and temperature. Tank must

be located in boiler return piping as close to boiler 2. Connect tank to ½" NPT tapping located behind

as possible, before inlet side of circulator. See tank

manufacturer’s instructions for details.

2. Install an automatic air vent in air vent tapping as

shown.

supply outlet, using ½" NPT piping. Pitch any

horizontal piping up towards tank 1 inch per 5 feet

of piping.

Undersized expansion tanks cause system water to be lost from relief valve and makeup water

to be added through fill valve. Eventual section failure can result.

Use Figure 4 or Figure 5 only for single-zone systems designed for return water at least 130 °F.

For systems with low return water temperature possible, such as converted gravity systems

and radiant heating systems, refer to the special piping suggestions of pages 18-23. Failure to

prevent low return water temperature to the boiler could cause corrosion of the boiler sections

or burners, resulting in severe personal injury, death or substantial property damage.

Figure 4 Diaphragm- or bladder-type expansion tank

Figure 5 Closed-type expansion tank

Piping to single-zone system using

diaphragm-type or bladder-type expansion

tank. See Table 3 for piping sizes.

Piping to single-zone system using closed-

type expansion tank. See Table 3 for piping

sizes.

Cold

water

fill

From

system

CLOSED-type

expansion tank

To DIAPHRAGM

expansion tank

and fittings

From

Cold water fill

system

Isolation

valve

Isolation

valve

Isolation

valve

Isolation

valve

Relief

valve

To system

Circulator*

To system

Relief

valve

Circulator*

Automatic

air vent

Circulator

Drain

valve

Drain

valve

Circulator

*Alternate

location

*Alternate

location

26010

26011

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GOLD CGs Gas-Fired Water Boiler

Water piping — multiple zones

Piping multiple zones

Follow instructions on pages 14 and 15 to install near-boiler or single-zone piping. (Also

refer to Piping for radiant heating systems or converted gravity systems, below, if

applicable.)

See Figure 6 or Figure 7 to complete installation.

1. Size each circulator to individual circuit requirements.

Zoning with

circulators, return

temp over 130 °F

2. Do not install circulator on boiler (except for primary/secondary piping).

3. Install isolation (balancing) valves to adjust flow to distribute heat to all zones.

4. Install and wire a separate relay for each zone circulator.

1. Install isolation (balancing) valves to adjust flow to distribute heat to all zones.

Zoning with zone

valves, return temp

over 130 °F

2. Provide a separate 24-volt transformer to power the zone valves. Size the transformer to

handle the total rated load of all connected zone valves.

Converted gravity (or steam) systems

Piping for radiant

heating systems or

converted gravity

systems

Whenever possible, use the primary/secondary piping shown in Figures 8 or 9 on page 19.

This piping design allows changing boiler flow rate without affecting primary circuit flow

rate.

If Figures 8 or 9 cannot be used, use the boiler-bypass piping shown in Figure 10 or Figure

11 on page 21. You can also use the piping shown in Figure 12 on page 23 (system-bypass), if

the reduced flow rate in the heating system will not cause heat distribution problems.

Failure to prevent low return water temperature to the boiler could cause corrosion of the

boiler sections or burners, resulting in severe personal injury, death or substantial property

damage.

Radiantheatingsystems

Preferably, use primary/secondary piping, as shown in Figures 8 or 9 on page 19.Alternatively,

use the method of either Figure 10 or Figure 11 on page 21. Do not use the piping of Figure

12 (system-bypass), because this method does not control radiant system supply temperature.

If radiant system tubing has no oxygen barrier, a heat exchanger must be used.

Radiant heating system piping should include a means of regulating the boiler return water

temperature and the system supply temperature (such as provided by an injection pumping

control). Boiler return water temperature will be adequately controlled using the methods

shown in this manual provided the system supply temperature is relatively constant.

Do not apply the methods in this manual if the system is equipped with an outdoor reset

control. Instead, provide controls and piping which can regulate the boiler return water

temperature at no less than 130 °F regardless of system supply temperature. Contact your

Weil-McLain representative for suggested piping and control methods. Failure to prevent

cold return water temperature to the boiler could cause corrosion damage to the sections or

burners, resulting in possible severe personal injury, death or substantial property damage.

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Boiler Manual

typical piping — multiple-zone installations

Figure 6

Figure 7

Zoning with circulators

— return water 130 °F or higher.

Zoning with zone valves

— return water 130 °F or higher.

ZONE 2

ZONE 1

Alternate

circulator

location

Cold

water

fill

Cold

water

fill

26012

26013

Boiler isolation (balancing) valves

Flow/check valve

System or zone circulator

Zone valve

air vent when using closed-type expansion tank. It

would allow air to leave the system, causing

waterlogging of the expansion tank.

11 Fill valve

12 Diaphragm-type or bladder-type expansion tank,

if used (For closed-type expansion tank, pipe from

top of air separator to tank fitting as in Figure 5.)

Drain valve

Relief valve

13 Air separator and automatic vent, if used (Note that

the fill valve must always be connected to the

expansion tank, regardless of location of expansion

tank circulator or air separator.

10 Automatic air vent (with diaphragm-type

expansion tank), or connect to tank fitting (closed-

type expansion tank). DO NOT use an automatic

For systems with possible low return-water temperature (such as converted gravity systems,

radiant heating systems and heat pump systems), refer to the special piping suggestions of

Figures 8 - 12, as applies. Failure to prevent sustained low return water temperature to the

boiler could cause corrosion of the boiler sections, resulting in severe personal injury, death

or substantial property damage.

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GOLD CGs Gas-Fired Water Boiler

Water piping — low temp systems

Primary/secondary

(preferred) bypass

piping method

Primary/secondary bypass piping is preferred because the flow rate and temperature drop in

the heating circuit(s) is determined only by the heating circuit circulator(s). So adjustment

of the bypass valves in the boiler circuit will not cause a change in the heating circuit rate and

temperature distribution.

Figures 8 and 9 show suggested bypass arrangements using primary/secondary bypass piping

(preferred) for low temperature systems such as radiant heating systems or converted gravity

systems. For alternatives, see pages 20 through 23.

The bypass valves (items 7a and 7b) provide mixing of hot boiler outlet water with cooler

system return water — set to assure a minimum return water temperature (at least 130 °F) to

the boiler. Set the valves as explained below.

Gauge 4a is suggested, but optional on any system.

Temperature gauges

Gauge 4b is optional on converted gravity systems, but required on radiant heating systems

— to display the water temperature being supplied to the radiant tubing.

Gauge 8 is required on all systems to assure the return water temperature is accurately set for

a minimum of 130 °F. If this gauge is not available however, adjust the valves such that the

boiler-mounted temperature/pressure gauge reads at least 150 °F when the system return

water is cold (approximately 60 °F water temperature).

Valve adjustment

(Figure 12 and 13 only)

1. Set the valves while the system is cool, setting for the coldest expected water temperature

(usually 60 °F since the system will often drop to room temperature between cycles).

2. Start with valve 7a fully closed and 7b fully open.

3. Gradually open valve 7a while closing valve 7b until the temperature at gauge 8 reads

130 °F when gauge 4a reads 60 °F.

4. Note that valve 7a regulates the amount of hot water from the boiler supply which mixes

with return water. Valve 7b regulates the amount of system water flowing through the

boiler secondary loop.

Failure to prevent low return water temperature to the boiler could cause corrosion of

the boiler sections or burners, resulting in severe personal injury, death or substantial property

damage.

Radiant heating system piping should include a means of regulating the boiler return

water temperature and the system supply temperature (such as provided by an injection

pumping control).

Boiler return water temperature will be adequately controlled using the methods shown in

this manual provided the system supply temperature is relatively constant.

DO NOT apply the methods of this manual if the system is equipped with an outdoor

reset control. Instead, provide controls and piping which can regulate the boiler return

water temperature at no less than 130 °F regardless of system supply temperature. Contact

your Weil-McLain representative for suggested piping and control methods.

Failure to prevent cold return water temperature to the boiler could cause corrosion

damage to the sections or burners, resulting in possible severe personal injury, death or

substantial property damage.

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primary/secondary (preferred) bypass piping —

for radiant heating or converted gravity systems

Figure 8

Figure 9

Zoning with circulators

Zoning with zone valves

ZONE 2

ZONE 1

ZONE 2

ZONE 1

12"

MAX.

12"

MAX.

Alternate

circulator

location

Alternate

circulator

location

Cold

water

fill

Cold

water

fill

26014

26015

Boiler isolation (balancing) valves

Flow/check valve

10 Automatic air vent (with diaphragm-type expansion

tank), or connect to tank fitting (closed-type expansion

tank). DO NOT use an automatic air vent when using

closed-type expansion tank. It would allow air to leave

the system, causing waterlogging of the expansion tank.

System or zone circulator

System temperature gauges

Zone valve

11 Fill valve

12 Diaphragm-type or bladder-type expansion tank, if

used (For closed-type expansion tank, pipe from top

of air separator to tank fitting as in Figure 5.)

Drain valve

System temperature valves (see instructions to the

left for adjusting valves)

13 Air separator and automatic vent, if used (Note that

the fill valve must always be connected to the expansion

tank, regardless of location of expansion tank,

circulator or air separator.)

Blend temperature gauge

Relief valve

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GOLD CGs Gas-Fired Water Boiler

Boiler-bypass piping

method

Water piping — low temp systems

This piping method is called a boiler-bypass because part of the circulator flow is bypassed

around the boiler (through valve 7a). This method reduces the flow rate throughout the

boiler, in order to raise the average water temperature in the boiler enough to prevent flue gas

condensation. Boiler-bypass piping is effective for some boilers — including the CGs —

provided the flow rates are adjusted according to the instructions following.

Figures 10 and 11 are alternative piping suggestions for converted gravity (large water content

or steam systems) or radiant heating system — for use when primary/secondary piping

can’t be applied. (Figure 12 is another alternative, using system bypass in place of boiler-

bypass piping. Figure 12 however, is not suitable for radiant heating applications because it

does not protect the radiant system from possible high water temperature.)

Boiler-bypass piping keeps system flow rate as high as possible and temperature drop as low

as possible, helping to equalize the building heat distribution.

Temperature gauges Gauge 4a is optional if the bypass valves will be adjusted using cold (or room temperature)

return water to the boiler. (When setting the valves without gauge 4a installed — using cold

or room temperature water — assume the return water temperature to be 60 °F. Set the valves

so gauge 8 reads at least 120 °F.

Gauge 4b is optional on converted gravity systems, but required on radiant heating systems

— to display the water temperature being supplied to the radiant tubing.

Gauge 8 is required on all systems to assure reliable adjustment of the bypass valves. The

boiler-mounted temperature/pressure gauge can be used if a separate temperature gauge is

not installed.

1. Start with valve 7a fully closed and 7b fully open.

Valve adjustment

2. Gradually open valve 7a while closing valve 7b until the temperature at gauge 8 reads

60 °F higher than gauge 4a. A minimum 60 °F temperature rise through the boiler assures

a low enough flow rate and high enough average temperature to prevent condensation

even with low system return water temperature.

3. Valve 7a regulates the system flow rate, while valve 7b regulates the boiler flow rate.

4. The boiler-mounted temperature/pressure gauge may be used in place of a separate

gauge 8.

Failure to prevent low return water temperature to the boiler could cause corrosion of

the boiler sections or burners, resulting in severe personal injury, death or substantial property

damage.

Radiant heating system piping should include a means of regulating the boiler return

water temperature and the system supply temperature (such as provided by an injection

pumping control).

Boiler return water temperature will be adequately controlled using the methods shown in

this manual provided the system supply temperature is relatively constant.

DO NOT apply the methods of this manual if the system is equipped with an outdoor

reset control. Instead, provide controls and piping which can regulate the boiler return

water temperatureat no less than 130 °F regardless of system supply temperature. Contact

your Weil-McLain representative for suggested piping and control methods.

Failure to prevent cold return water temperature to the boiler could cause corrosion

damage to the sections or burners, resulting in possible severe personal injury, death or

substantial property damage.

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boiler-bypass (alternate) piping —

for radiant heating or converted gravity systems

Figure 10 Boiler-bypass piping

Figure 11 Boiler-bypass piping

Zoning with circulators

Zoning with zone valves

(Alternative to primary/secondary piping

Figures 8 and 9)

(Alternative to primary/secondary piping

Figures 8 and 9)

ZONE 2

ZONE 1

ZONE 2

ZONE 1

Alternate

circulator

location

Cold

water

fill

Cold

water

fill

26016

26017

10 Automatic air vent (with diaphragm-type

expansion tank), or connect to tank fitting (closed-

type expansion tank). DO NOT use an automatic

air vent when using closed-type expansion tank. It

would allow air to leave the system, causing

waterlogging of the expansion tank.

Boiler isolation (balancing) valves

Flow/check valve

System or zone circulator

System temperature gauges

Zone valve

11 Fill valve

12 Diaphragm-type or bladder-type expansion tank,

if used (For closed-type expansion tank, pipe from

top of air separator to tank fitting as in Figure 5.)

Drain valve

System temperature valves (see instructions to the left

for adjusting valves)

13 Air separator and automatic vent, if used (Note that

the fill valve must always be connected to the

expansion tank, regardless of location of expansion

tank, circulator or air separator.)

Blend temperature gauge

Relief valve

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GOLD CGs Gas-Fired Water Boiler

System-bypass

piping method

Water piping — low temp systems

This piping method is called a system-bypass because part of the circulator flow bypasses

the system (through valve 7a). This bypassed hot water from the boiler outlet mixes with

cooler system return water temperature in order to provide minimum 130 °F return water to

the boiler. Valve 7b will most often be full open, but may need to be slightly closed on some

low pressure drop systems in order to cause enough flow through valve 7a.

Figure 12 is an alternative piping method that provides return water temperature control for

boilers installed on converted gravity systems (large water content or steam systems).

Do not apply the piping of Figure 12 on radiant heating systems. It provides no method

regulating the water temperature provided to the system and could result in excessive water

temperature in the radiant tubing.

System-bypass piping as shown in Figure 12 can be used with either zone valve or circulator

zoning. When used with circulator zoning however, the boiler circulator (item 3), must be

piped as shown. It cannot be used as one of the zoning circulators.

Do not apply system-bypass piping if the reduced flow in the system could cause poor heat

distribution. That is, system-bypass piping reduces the flow in the system and increases the

water temperature supplied to the system. This can cause increased heat from radiators at the

beginning of the system and reduced heat from radiators near the end of the system.

Valve adjustment 1. Start with valve 7a fully closed and 7b fully open.

2. Gradually open valve 7a while closing valve 7b until the temperature at gauge 8 reads at

least 130 °F at all times.

3. Valve 7a regulates the amount of boiler supply water mixed with return water. Valve 7b

causes a pressure drop in the system needed to balance flow through valve 7a and the

system.

4. The valve adjustment should be done with the system at the coldest expected temperature

(60 °F for converted gravity systems or high mass radiant systems).