Weil Mclain Gold Cga Users Manual

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Boiler Manual

Part Number 550-110-593/1099 5

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

or substantial property damage.

Please read before proceeding

and/or property may result.

• 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.

• Do not add cold water to hot boiler. Thermal

shock can cause sections to crack.

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 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 supply at a

location external to the appliance.

• Do not use this boiler if any part has been under

water. Immediately call a qualified service

technician to inspect the boiler and to replace any

part of the control system and any gas control that

has been under water.

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.

• Do not use "homemade cures" or "boiler patent

medicines". Serious damage to boiler, personnel

Installer

Read all instructions before

installing. Follow all instructions in

proper order to prevent personal

injury or death.

• 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.

User

•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.

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 33.

Glycol — potential fire hazard —

All glycol is flammable when exposed to high

temperatures. If glycol is allowed to accumulate in or

around the boiler or any other potential ignition

source, a fire can develop. In order to prevent potential

severe personal injury, death or substantial 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.

• Never use automotive antifreeze or ethylene glycol

in the system. Using these glycols can lead to

hazardous leakage of glycol in the boiler system.

GOLD CGa Gas-Fired Water Boiler

2Part Number 550-110-593/1099

How it works . . .

①Control module

The control module (used on spark-ignited pilot boilers) responds to signals from the room thermostat and

boiler limit circuit to operate the boiler circulator, pilot burner, gas valve and vent damper. When room thermostat

calls for heat, the control module starts the system circulator and activates the vent damper (causing it to drive

open).

When the vent damper has opened completely, the control module opens the pilot valve and activates pilot ignition

spark.

The control module allows up to 15 seconds to establish pilot flame. If flame is not sensed within 15 seconds, the

control module will turn off the gas valve, flash the Flame light, and immediately start a new cycle. This will

continue indefinitely until pilot flame is established or power is interrupted. Once pilot flame is proven, the control

module opens the gas valve to allow main burner flame.

When the room thermostat is satisfied, the control module turns off the gas valve and deactivates the vent damper

(causing it to close).

The control module indicator lights show normal sequence when the lights are on steady. When a problem occurs,

the control module flashes combinations of lights to indicate the most likely reason for the problem. See page 52

for details.

Standing pilot boilers (controls not shown) use the pilot thermocouple to prove flame. If the thermocouple is

satisfied, the gas valve and vent damper will open on a call for heat and close afterwards.

②Transformer

The control transformer reduces line voltage to 24 volts for the gas valve and limit circuit.

③Draft hood

The draft hood provides a minimum draft for the boiler, assuring adequate air for combustion if installed in

accordance with manual and not modified in any way.

④Spill switch

The spill switch will shut down the boiler (requiring manual reset of the switch reset button) if the vent system

becomes blocked.

⑤Water temperature limit switch

The water temperature limit switch turns off the gas valve if the temperature in the boiler goes above its setting.

(The circulator will continue to run as long as there is a call for heat.)

Boiler circulator

The boiler circulator circulates water through the external (system) piping. The circulator is shipped loose, and

can be mounted on either the boiler supply or return piping. The factory-installed circulator wiring harness

provides ample length for either location. NOTE — The control module provides a pump exercising routine. If the

boiler is not operated for 30 days, the control module will power the circulator for 30 seconds, then turn off.

⑦Vent damper

The vent damper closes during off cycles to reduce heat loss from the house up the vent.

asupply to system

breturn from system

cflue outlet

dburner manifold

egas valve

fpressure/temperature gauge

grelief valve

hair vent connection

iflame rollout switch

jburner orifice

kpilot burner, typical

lstainless steel burners

mcast iron boiler sections

nflue collector

ojunction box

Other boiler components:

GOLD CGa Gas-Fired Water Boiler

4Part Number 550-110-593/1099

Contents

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.

Standing pilot Spark-ignited pilot

How it works 2–3

Hazard definitions 4

Please read before proceeding 5

1. Prepare boiler location 6–11

2. Prepare boiler 12–15

3. Water piping 16–25

4. Gas piping 26

5. Field wiring 27

6. Start-up 28–32

7. Check-out procedure 33

8. Operation — standing pilot boilers 34–36

9. Operation — spark-ignited pilot boilers 37–43

10. Service and maintenance 44–49

11. Troubleshooting 49–50, 51 49–50, 51–59

12. Replacement parts 60–65

13. Dimensions and ratings 66–67

GOLD CGa Gas-Fired Water Boiler

6Part Number 550-110-593/1099

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

regulations and ordinances.

• National Fuel Gas Code, ANSI Z223.1–latest edition.

• Standard for Controls and Safety Devices for

Automatically Fired Boilers, ANSI/ASME CSD-1,

when required.

Prepare boiler location —

codes & checklist

Installations must follow these codes:

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.

• 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.

• 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.

Fresh air

opening

59305

Top view Side elevation

Figure 1

Minimum clearances

(see page 7)

Boiler Manual

Part Number 550-110-593/1099 7

Prepare boiler location — clearances1b

Service clearances

1. Provide the following clearances for cleaning and

servicing the boiler and for access to controls and

components:

Flooring and foundation

Flooring

The CGa boiler is approved for installation on

combustible flooring, but must never be installed on

carpeting.

Do not install boiler on carpeting

even if foundation is used. Fire can

result, causing severe personal

injury, death or substantial property

damage.

Foundation

1. 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.

2. The minimum foundation size is:

Residential garage installation

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.

Small space installations

1. Provide the following clearances to combustible

material for small space installations.

(See Figure 1, page 6):

2. Hot water pipes must be at least ¹⁄₂" from

combustible material.

3. Single-wall vent pipe must be at least 6 inches

from combustible material.

4. Type B double-wall metal vent pipe — refer to

vent manufacturer’s recommendation for clearances

to combustible material.

Boiler

model

Minimum

foundation

length

Minimum

foundation

width

CGa-25 25" 12"

CGa-3 25" 12"

CGa-4 25" 15"

CGa-5 25" 18"

CGa-6 25" 21"

CGa-7 25" 24"

CGa-8 25" 27"

2. Provide at least screwdriver clearance to jacket front

panel screws for removal of front panel for

inspection and minor service. If unable to provide

at least screwdriver clearance, install unions and

shutoff valves in system so boiler can be moved for

servicing.

Clearance from: Minimum

Top

(for cleaning flueways)

35"

Front

(for access to controls and components)

18"

Back 7"

Left side

(for cleaning and servicing)

24"

Right side 7"

Clearance from combustible

materials (closet installations):

Minimum

Top (for cleaning flueways) 35"

Front (provide means of access) 3"

Back 7"

Left side (provide means of access) 6"

Right side 2"

GOLD CGa Gas-Fired Water Boiler

8Part Number 550-110-593/1099

Prepare boiler location — vent system1c

Failure to follow all instructions can result in flue gas spillage and carbon monoxide emissions, causing severe

personal injury or death.

When removing boiler from

existing common vent system:

At the time of removal of an existing boiler, the following

steps shall be followed with each appliance remaining

connected to the common venting system placed in

operation, while the other appliances remaining

connected to the common venting system are not in

operation.

a. Seal any unused openings in the common venting

system.

b. Visually inspect the venting system for proper

size and horizontal pitch and determine there is no

blockage or restriction, leakage, corrosion or other

deficiencies which could cause an unsafe condition.

c. Test vent system — Insofar as is practical, close all

building doors and windows and all doors between

the space in which the appliances remaining

connected to the common venting system are

located and other spaces of the building. Turn on

clothes dryers and any appliance not connected to

the common venting system. Turn on any exhaust

fans, such as range hoods and bathroom exhausts,

so they will operate at maximum speed. Do not

operate a summer exhaust fan. Close fireplace

dampers.

d. Place in operation the appliance being inspected.

Follow the lighting/operating instructions. Adjust

thermostat so appliance will operate continuously.

e. Test for spillage at draft hood relief opening after

5 minutes of main burner operation. Use the flame

of a match or candle.

f. After it has been determined that each appliance

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 appliance to their

previous conditions of use.

Any improper operation of common venting system

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 11 of

that code. Canadian installations must comply with

B149.1 or B149.2 Installation Code.

Chimney or vent requirements

1. Venting must be installed according to Part 7,

Venting of Equipment, of National Fuel Gas Code,

ANSI Z223.1-latest edition and applicable building

codes. Canadian installations must comply with

B149.1 or B149.2 Installation Codes.

2. See Ratings table on page 67 for minimum chimney

or vent sizes. A chimney or vent without a listed

cap should extend at least 3 feet above the highest

point where it passes through a roof of a building

and at least 2 feet higher than any portion of a

building within a horizontal distance of 10 feet.

A chimney or vent must not extend less than the

distances stated above.

3. A lined chimney is preferred and must be used when

required by local, state, provincial and national

codes, laws, regulations and ordinances. Vitreous tile

linings with joints that prevent retention of moisture

and linings made of noncorrosive materials are best.

Advice for flue connections and chimney linings can

be obtained from local gas utility. Type B double-

wall metal vent pipe or single-wall vent pipe may

be used as a liner.

4. Cold masonry chimneys, also known as outside

chimneys, typically have one or more walls exposed

to outside air. When any atmospheric gas-fired

boiler with automatic vent damper is vented

through this type of chimney, the potential exists

for condensation to occur. Condensation can

damage a masonry chimney. Weil-McLain

recommends the following to prevent possible

damage.

a. Line chimney with corrosion-resistant metal

liner such as AL29-4C® single-wall stainless steel

or B-vent. Size liner per National Fuel Gas Code

ANSI Z223.1-latest edition.

b. Provide drain trap to remove any condensate.

5. Where two or more gas appliances vent into a

common chimney or vent, equivalent area should

be at least equal to area of vent outlet on largest

appliance plus 50 percent of vent outlet area on

additional appliance.

Do not alter boiler draft hood or place any obstruction or non-approved vent damper in breeching or vent system.

CSA certification will become void. Flue gas spillage and carbon monoxide emissions will occur causing severe

personal injury or death.

Inspect existing chimney before installing boiler. Failure to clean or replace perforated pipe or tile lining will cause

severe personal injury or death.

Boiler Manual

Part Number 550-110-593/1099 9

Prepare boiler location — air contamination

Table 1 Corrosive contaminants and likely locations

To prevent potential of severe personal injury or death, check for products or areas listed below

before installing boiler. If any of these contaminants are found:

• remove contaminants permanently

— OR —

• isolate boiler and provide outside combustion air. See national, provincial or local codes

for further information.

Please review the following information on potential

combustion air contamination problems. Refer to Table 1 for products and areas which may cause

contaminated combustion air.

Products to avoid Areas likely to have contaminants

Spray cans containing chloro/fluorocarbons Dry cleaning/laundry areas and establishments

Permanent wave solutions Swimming pools

Chlorinated waxes/cleaners Metal fabrication plants

Chlorine-based swimming pool chemicals Beauty shops

Calcium chloride used for thawing Refrigeration repair shops

Sodium chloride used for water softening Photo processing plants

Refrigerant leaks Auto body shops

Paint or varnish removers Plastic manufacturing plants

Hydrochloric acid/muriatic acid Furniture refinishing areas and establishments

Cements and glues New building construction

Antistatic fabric softeners used in clothes dryers Remodeling areas

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

GOLD CGa Gas-Fired Water Boiler

10 Part Number 550-110-593/1099

Combustion air and ventilation openings must comply

with Section 5.3, Air for Combustion and Ventilation,

of National Fuel Gas Code ANSI Z223.1-latest edition,

or applicable local building codes. Canadian

installations must comply with B149.1 or B149.2

Installation Codes.

Provide adequate combustion and

ventilation air to assure proper

combustion and reduce the risk of

severe personal injury, death or

substantial property damage caused

by flue gas spillage and carbon

monoxide emissions.

Air from inside building

(boiler in interior room - Figure 2)

1. Tightly constructed buildings must be provided with

openings to outside for combustion and ventilation

air. These openings must be sized to handle all fuel

burning appliances, exhaust or ventilation fans and

fireplaces.

2. When openings to boiler room are taken to interior

spaces, provide two permanent openings:

• One air opening within 12 inches of floor.

• A second opening within 12 inches of ceiling.

Each opening must provide a minimum free area

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

appliances in room plus requirements for any

exhaust fans in room. The interior space supplying

combustion and ventilation air must have adequate

infiltration from outside.

1. Tightly constructed buildings must be provided with

combustion and ventilation air openings to boiler

room, which are adequate to handle the boiler needs

plus the needs of all other fuel burning appliances,

exhaust or ventilation fans and fireplaces.

2. When combustion air is supplied to the boiler space

directly through outside walls (Figure 3): Provide

two permanent openings:

• One air opening within 12 inches of floor.

• A second opening within 12 inches of ceiling.

Each opening must provide a minimum free area

of 1 square inch per 4,000 Btuh of input of all

appliances in room plus requirements for any

exhaust fans in room.

Prepare boiler location — air openings1c

MODEL

CGi

MODEL

CGi

Boiler Manual

Part Number 550-110-593/1099 11

Special considerations

Tight construction

ANSI Z223.1 defines unusually tight construction

where:

a. Walls and ceilings exposed to the outside

atmosphere have a continuous water vapor retarder

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,

between wall panels, at penetrations for plumbing,

electrical, and gas lines, and in other openings.

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.

Air

opening

Air

opening

0 to 12"

Other

appliances

CGa

boiler

GOLD CGa Gas-Fired Water Boiler

12 Part Number 550-110-593/1099

Prepare boiler — placement and setup

Table 2 Manifold orifice sizing

Inspect orifices and burners

1. Remove front jacket door. Remove base access panel

(See Figure 32, item 4, page 62).

2. Check for correctly-sized manifold orifices. See Table

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

the orifice spud barrel.)

Correctly-sized manifold orifices

must be used. Failure to do so will

result in severe personal injury,

death or substantial property

damage.

3. Level and straighten burners.

Burners must be properly seated in

slots in burner rest with their

openings face up. Main burner

orifices must inject down center of

Place boiler/crate near position

1. Leave boiler in crate and on pallet until installation

site is ready.

2. Move entire crate and pallet next to selected

location.

3. Remove crate. Leave boiler on pallet.

4. Remove boiler from pallet as follows:

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

under left legs.

b. Tilt boiler the other way and place a board

under right legs.

c. Slide boiler backwards off pallet and into

position. Do not drop boiler or bump jacket

on floor or pallet. Damage to boiler

can result.

5. Check level.

a. Shim legs, if necessary.

b. Do not alter legs.

Orifice replacement procedure

(when required)

1. Remove access panel.

2. On gas manifold, mark location of main burner with

attached pilot assembly.

3. Remove main burner with attached pilot assembly

from manifold. Remove all remaining burners.

4. Remove and discard all main burner orifices in gas

manifold.

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

new orifices and install in the manifold. Make sure

the orifices are aligned correctly, not cross-threaded

in the manifold tappings.

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.

6. Reinstall main burner with attached pilot assembly

at location marked on gas manifold. Reinstall all

remaining burners.

7. Follow check-out procedure, section 7, page 33.

burner. Failure to properly seat

burners will result in severe personal

injury, death or substantial property

damage.

4. Reinstall access panel.

Do not operate boiler without access

panel secured in place. Failure to

comply could cause momentary

flame rollout on ignition of main

flame, resulting in possible fire or

personal injury hazard.

Location Natural gas Propane gas

U. S.

0-2,000 ft over 2,000 ft 0-2,000 ft over 2,000 ft

2.00 mm (Note 1) 1.30 mm (Note 1)

Canada

0-2,000 ft 2,000-4,500 0-2,000 ft 2,000-4,500

2.00 mm 1.90 mm 1.30 mm 1.20 mm

Note 1:

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

Boiler Manual

Part Number 550-110-593/1099 13

Prepare boiler — pressure test

Perform hydrostatic pressure test

Pressure test boiler before attaching water or gas piping

or electrical supply (except as noted below).

3. When water flows from shutoff valves, close boiler

drain valve.

4. Close shutoff valves.

5. Slowly reopen boiler drain valve until test pressure

of not more than 45 psi is reached on the pressure/

temperature gauge.

6. Test at no more than 45 psi for no more than 10

minutes.

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.

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 3

to replace relief valve.

Do not use petroleum-based

cleaning or sealing compounds in

boiler system. Severe damage to

boiler will occur, resulting in

substantial property damage.

Leaks must be repaired at once.

Failure to do so can damage boiler,

resulting in substantial property

damage.

7. Make sure constant gauge pressure has been

maintained throughout test. Check for leaks. Repair

if found.

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.

Prepare boiler for test

1. Remove the shipping nipple (from CGa 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 or in Figure 34, item

3, page 64. 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 in Figure 34, page 64.

(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.)

GOLD CGa Gas-Fired Water Boiler

14 Part Number 550-110-593/1099

Boiler Manual

Part Number 550-110-593/1099 15

Prepare boiler — vent damper installation

These systems are used on gas-fired boilers with vent dampers as shipped from factory. Boiler will not operate

without vent damper installed.

Only vent dampers listed in the Replacement parts list on page 61 are certified for use with CGa boilers. Any

other vent damper installed could cause severe personal injury or death.

4. Read and apply the harness plug warning label

(shown above) so that it is visible after installation.

5. Plug damper harness receptacle into damper harness

plug.

Bypassing (jumpering) vent damper

will cause flue products such as

carbon monoxide to escape into the

house. This will cause severe

personal injury or death.

After boiler has operated once, if

either end of harness is

disconnected, the system safety

shutdown will occur. The boiler will

not operate until harness is

reconnected.

Effikal damper — Damper hold

open switch must be in Automatic

Operation position for system to

operate properly.

Figure 8 Vent damper assemblies

Damper blade

Standing pilot ignition systems— Refer to vent

manufacturer’s instructions to install plug (shipped with

damper) in damper hole. For standing pilot boilers only,

install plug with 3

8" diameter hole in vent damper

hole.

Spark-ignited pilot systems— Refer to vent

manufacturer’s instructions to install plug (shipped with

damper) in damper hole. For spark-ignited pilot boilers only,

install plug with no hole in veper

GOLD CGa Gas-Fired Water Boiler

16 Part Number 550-110-593/1099

Water piping — general information3a

Boiler model To

system

From

system

CGa-25 ¾" ¾"

CGa-3 1" 1"

CGa-4 1" 1"

CGa-5 1" 1"

CGa-6 1¼" 1¼"

CGa-7 1¼" 1¼"

CGa-8 1½" 1½"

Note: Circulator flange supplied with boiler is same size as

recommended piping above.

General piping information

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

page 34 or 38, for wiring.

Alow 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.

Relief valve

Install relief valve vertically in ¾" tapping on side of boiler. See Figure 9 or

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

To avoid water damage or scalding due to relief valve

operation:

• 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.

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

the valve discharge connection throughout its entire length.

• Discharge line must pitch downward from the valve and terminate

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

visible.

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

material serviceable for temperatures of 375 °F or greater.

•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.

•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.

System water piping

See Figure 9 (diaphragm-type or bladder-type

expansion tank) or Figure 10 (closed-type expansion

tank) on page 21, and Table 3 below, for near-boiler and

single-zone systems designed for return water at least

130 °F.

See pages 18-19 to complete multiple-zone piping or

pages 20-25 to complete piping for radiant heating

systems or converted gravity systems.

Refer to page 25 for boilers used with refrigeration systems.

Install boiler such that —

• 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.

• 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.

Pressure/temperature gauge

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.

Boiler Manual

Part Number 550-110-593/1099 17

Expansion tank

Diaphragm-type or bladder-type

expansion tank — Figure 9

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

as possible, before inlet side of circulator. See tank

manufacturer’s instructions for details.

2. Install an automatic air vent as shown.

Closed-type expansion tank — Figure 10

1. Ensure expansion tank size will handle boiler and

system water volume and temperature. See tank

manufacturer’s instructions for details.

2. Connect tank to ½" NPT tapping located behind

supply outlet, using ½" NPT piping. Pitch any

horizontal piping up towards tank 1 inch per 5 feet

of piping.

Use Figure 9 or Figure 10 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 20-25. 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.

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.

Water piping — single-zone system

Figure 9

Diaphragm- or bladder-type expansion tank

Piping to single-zone system using

diaphragm-type or bladder-type expansion

tank. See Table 3 for piping sizes.

Figure 10 Closed-type expansion tank

Piping to single-zone system using closed-

type expansion tank. See Table 3 for piping

sizes.

59306

CGa

GOLD

From

system

Cold

water

fill

To DIAPHRAGM

expansion tank

and fittings

Isolation

valve Isolation

valve

To system

Circulator*

Circulator

Drain

valve

Relief

valve

Automatic

air vent

*Alternate

location

59307

To system

From

system

Isolation

valve

Drain

valve

Relief

valve Circulator*

Isolation

valve

Circulator

Cold water fill

CLOSED-type

expansion tank

*Alternate

location

CGa

GOLD

GOLD CGa Gas-Fired Water Boiler

18 Part Number 550-110-593/1099

Water piping — multiple zones

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 systems

Preferably, use primary/secondary piping, as shown in Figures 13 or14 on page 21. Alternatively,

use the method of either Figure 15 orFigure 16 on page 23. Do not use the piping of Figure

17 (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.

Boiler Manual

Part Number 550-110-593/1099 19

Typical piping — multiple-zone installations

Figure 11

Zoning with circulators

— return water 130 °F or higher.

Figure 12

Zoning with zone valves

— return water 130 °F or higher.

1Boiler isolation (balancing) valves

2Flow/check valve

3System or zone circulator

5Zone valve

6Drain valve

9Relief 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.

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 10.)

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.

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 13 – 17, 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.

59308

Cold

water

fill

GOLD

CGa

ZONE 2

ZONE 1

59309

Cold

water

fill

GOLD

CGa

ZONE 2

ZONE 1

Alternate

circulator

location

GOLD CGa Gas-Fired Water Boiler

20 Part Number 550-110-593/1099

Water piping — low temp systems

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.

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 13 and 14 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 22 through 25.

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.

Primary/secondary

(preferred) bypass

piping method

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

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).

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.

Valve adjustment

(Figure 13 and 14 only)

Boiler Manual

Part Number 550-110-593/1099 21

Primary/secondary (preferred) piping —

for radiant heating or converted gravity systems

1Boiler isolation (balancing) valves

2Flow/check valve

3System or zone circulator (circulator should cycle

with zone valve and switches, using circulator valve

or zone control panel)

4System temperature gauges

5Zone valve

6Drain valve

7System temperature valves (see instructions to the

left for adjusting valves)

8Blend temperature gauge

9Relief 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.

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 10.)

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.)

Figure 13

Zoning with circulators

Figure 14

Zoning with zone valves

59310

GOLD

CGa

ZONE 2

ZONE 1

4a 4b 3

12"

MAX.

Cold

water

fill

Alternate

circulator

location

59311

Cold

water

fill

GOLD

CGa

ZONE 2

ZONE 1

12"

MAX.

4a 4b

7b 13

Alternate

circulator

location

GOLD CGa Gas-Fired Water Boiler

22 Part Number 550-110-593/1099