Weil Mclain Gold Cga Users Manual

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2015-02-02

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Boiler Manual

Please read before proceeding
Installer

•
•

User
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.

•
•

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.

Failure to adhere to the guidelines on this page can result in severe personal injury, death
or substantial property damage.

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

Part Number 550-110-593/1099

•

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.

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

How it works . . .

①

Control 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

②
③
④
⑤

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

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

Draft 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.

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

Water 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

⑦

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.

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

Other boiler components:
a
b
c
d
e
2

supply to system
return from system
flue outlet
burner manifold
gas valve

f
g
h
i
j

pressure/temperature gauge
relief valve
air vent connection
flame rollout switch
burner orifice

k
l
m
n
o

pilot burner, typical
stainless steel burners
cast iron boiler sections
flue collector
junction box

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Contents
Standing pilot

Spark-ignited pilot
2–3

How it works
Hazard definitions

Please read before proceeding

1. Prepare boiler location

6–11

2. Prepare boiler

12–15

3. Water piping

16–25

4. Gas piping

5. Field wiring

27
28–32

6. Start-up

7. Check-out procedure
8. Operation — standing pilot boilers

34–36
37–43

9. Operation — spark-ignited pilot boilers
44–49

10. Service and maintenance
11. Troubleshooting

49–50, 51

49–50, 51–59

12. Replacement parts

60–65

13. Dimensions and ratings

66–67

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.

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Prepare boiler location — codes & checklist
Installations must follow these codes:
•

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.

•

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.

Before locating the boiler, check the following:
•

•

Check for nearby connection to:
• System water piping
• Venting connections
• Gas supply piping
• Electrical power

•

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.

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.

Figure 1
6

Minimum clearances
(see page 7)

Fresh air
opening
7

3
59305

Top view

Side elevation

Part Number 550-110-593/1099

Boiler Manual

Prepare boiler location — clearances
Service clearances

Flooring and foundation

1. Provide the following clearances for cleaning and
servicing the boiler and for access to controls and
components:

Flooring

Clearance from:
Top (for cleaning flueways)
Front (for access to controls and components)
Back
Left side (for cleaning and servicing)
Right side

The CGa boiler is approved for installation on
combustible flooring, but must never be installed on
carpeting.

Minimum

Do not install boiler on carpeting
even if foundation is used. Fire can
result, causing severe personal
injury, death or substantial property
damage.

35"
18"
7"
24"
7"

Foundation
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.

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:
Boiler
model

Small space installations
1. Provide the following clearances to combustible
material for small space installations.
(See Figure 1, page 6):
Clearance from combustible
materials (closet installations):
Top (for cleaning flueways)
Front (provide means of access)
Back
Left side (provide means of access)
Right side

Minimum
35"
3"
7"
6"
2"

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.
Part Number 550-110-593/1099

CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8

Minimum
foundation
length
25"
25"
25"
25"
25"
25"
25"

Minimum
foundation
width
12"
12"
15"
18"
21"
24"
27"

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.
7

GOLD CGa Gas-Fired Water Boiler

Prepare boiler location — vent system
Failure to follow all instructions can result in flue gas spillage and carbon monoxide emissions, 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.
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.

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.
8

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 doublewall 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.
Part Number 550-110-593/1099

Boiler Manual

Prepare boiler location — air contamination
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.

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.

Table 1 Corrosive contaminants and likely locations

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

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Prepare boiler location — air openings
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.

Air directly from outside to
boiler room
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.

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.

MODEL

CGi

Part Number 550-110-593/1099

Boiler Manual

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

0 to 12"

CGa
boiler

Air
opening

Other
appliances

0 to 12"

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Prepare boiler — placement and setup
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.

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.)

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.

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.

Correctly-sized manifold orifices
must be used. Failure to do so will
result in severe personal injury,
death or substantial property
damage.

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.

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

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.

Table 2 Manifold orifice sizing
Location

Natural gas

Propane gas

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)

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

U. S.

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

Part Number 550-110-593/1099

Boiler Manual

Prepare boiler — pressure test
Perform hydrostatic pressure test
Pressure test boiler before attaching water or gas piping
or electrical supply (except as noted below).

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.)

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.
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.

Fill and pressure test

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

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

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

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

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

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Part Number 550-110-593/1099

Boiler Manual

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.
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

Figure 8

Vent damper assemblies

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.
Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Water piping — general information

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.
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.

Pressure/temperature gauge

System water piping

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.

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.

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.

Boiler model
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8

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.

From
system
¾"
1"
1"
1"
1 ¼"
1 ¼"
1 ½"

Note: Circulator flange supplied with boiler is same size as
recommended piping above.

Install boiler such that —
•

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.

To
system
¾"
1"
1"
1"
1 ¼"
1 ¼"
1 ½"

•

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.
Part Number 550-110-593/1099

Boiler Manual

Water piping — single-zone system
Expansion tank
Closed-type expansion tank — Figure 10

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.

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.

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 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.
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.
From
system

Figure 10 Closed-type expansion tank
Piping to single-zone system using closedtype expansion tank. See Table 3 for piping
sizes.

Cold
water
fill

CLOSED-type
expansion tank

To DIAPHRAGM
expansion tank
and fittings
Isolation
valve

From
system

Isolation
valve

Relief
valve

To system

Isolation
valve

Cold water fill
Isolation
valve
To system

Circulator*
Automatic
air vent

Relief
valve

Circulator*

GOLD

CGa

GOLD

CGa

Circulator

Drain
valve

Circulator
59306

Part Number 550-110-593/1099

*Alternate
location

59307

*Alternate
location

GOLD CGa Gas-Fired Water Boiler

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 or 14 on page 21. Alternatively,
use the method of either Figure 15 or Figure 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.

Part Number 550-110-593/1099

Boiler Manual

Typical piping — multiple-zone installations
Figure 11

Figure 12

Zoning with circulators
— return water 130 °F or higher.

Zoning with zone valves
— return water 130 °F or higher.

ZONE 2

ZONE 1

1
2

1
13

6
1

1
Alternate
circulator
location

9
Cold
water
fill

Cold
water
fill
CGa

11
12

GOLD

CGa

59309

59308

1
2
3
5
6
9
10

Boiler isolation (balancing) valves
Flow/check valve
System or zone circulator
Zone valve
Drain valve
Relief valve
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.
Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

3d
Primary/secondary
(preferred) bypass
piping method

Water piping — low temp systems
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.

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).

Valve adjustment
(Figure 13 and 14 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.

Part Number 550-110-593/1099

Boiler Manual

Primary/secondary (preferred) piping —
for radiant heating or converted gravity systems
Figure 13

Figure 14

Zoning with circulators

Zoning with zone valves

ZONE 2

ZONE 1

ZONE 1
1

1
2

1
4a
2
1

12"
MAX.

1
7b

Alternate
circulator
location

9
Cold
water
fill

3
7b

Alternate
circulator
location

7a
8

12"
MAX.

Cold
water
fill

11
GOLD

CGa

GOLD

CGa

59311

59310

Boiler isolation (balancing) valves

Flow/check valve

System or zone circulator (circulator should cycle
with zone valve and switches, using circulator valve
or zone control panel)

System temperature gauges

Zone valve

Drain valve

System temperature valves (see instructions to the
left for adjusting valves)

Blend temperature gauge

Relief valve

Part Number 550-110-593/1099

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.)

GOLD CGa Gas-Fired Water Boiler

3e
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 CGa —
provided the flow rates are adjusted according to the instructions following.
Figures 15 and 16 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 17 is another alternative, using system bypass in place of boiler-bypass
piping. Figure 17 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.

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

Part Number 550-110-593/1099

Boiler Manual

Boiler-bypass (alternate) piping —
for radiant heating or converted gravity systems
Figure 15

Boiler-bypass piping

Figure 16

Boiler-bypass piping

Zoning with circulators

Zoning with zone valves

(Alternative to primary/secondary piping
Figures 13 and 14)

ZONE 2

ZONE 1

1
2
4a

13 1

2
6

7b
9

4a
GOLD

Alternate
circulator
location

Cold
water
fill

CGa

Cold
water
fill

11
GOLD

CGa

12
3

59312

59313

10 Automatic air vent (with diaphragm-type expansion

Boiler isolation (balancing) valves

Flow/check valve

System or zone circulator

System temperature gauges

Zone valve

11 Fill valve

Drain valve

12 Diaphragm-type or bladder-type expansion tank,

System temperature valves (see instructions to the left
for adjusting valves)

Blend temperature gauge

Relief valve

Part Number 550-110-593/1099

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.

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.)
23

GOLD CGa Gas-Fired Water Boiler

3f
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 17 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 17 on radiant heating systems. It provides no method of

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 17 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).

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

Part Number 550-110-593/1099

Boiler Manual

System-bypass

(alternate)

piping —

for converted gravity (or steam) systems
From system

To system

Zoning with zone valve or circulators, return
water 130 °F or higher.

Alternate
circulator
location

8
Cold
water
fill

Figure 17 System-bypass piping

11
GOLD

CGa

(Alternative to boiler-bypass piping Figures
15 and 16)
3

System or zone circulator

System temperature valves (see instructions to the left for
adjusting valves)

Blend temperature gauge

Relief 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.)

59314

Water piping — Refrigeration system
Figure 18 Piping refrigeration systems
Expansion tank

System
supply

Install boiler so that chilled medium
is piped in parallel with the heating
boiler. Use appropriate valves to
prevent chilled medium from
entering boiler. See Figure 18 for
typical installation of balancing
valve and check valve.

Shut-off
valve

Circulator

Water
chiller

Strainer
Check
valve
System
return

59315

Part Number 550-110-593/1099

Prevent chilled water from
entering boiler

Balancing
valve

Boiler

GOLD

CGa

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.
25

GOLD CGa Gas-Fired Water Boiler

Gas piping
Natural Gas:
1. Refer to Table 4 for pipe length and diameter. Base
on rated boiler input (divide by 1,000 to obtain cubic
feet per hour). Table 4 is only for gas with specific
gravity 0.60, with a pressure drop through the
gas piping of 0.30" w.c. For additional gas pipe

sizing information, refer to ANSI Z223.1 (or B149.1
or B149.2 for Canadian installations).
2. Inlet pressure required at gas valve inlet:
• Maximum: 13" w.c.
• Minimum: 5" w.c.
• Manifold gas pressure: 3.5" w.c.
3. Install 100% lockup gas pressure regulator in supply
line if inlet pressure exceeds 13" w.c. Adjust for
13" w.c. maximum.
Propane Gas:
1. Contact gas supplier to size pipes, tanks and 100%
lockup gas pressure regulator.
2. Adjust propane supply regulator provided by gas
supplier for 13" w.c. maximum pressure.
3. Inlet pressure required at gas valve inlet:
• Maximum: 13" w.c.
• Minimum: 11" w.c.
• Manifold gas pressure: 10" w.c.
Figure 19

Gas supply piping

Manual main
shutoff gas valve
(when required)

Table 4 Pipe capacity for 0.60 specific gravity natural gas
Ground joint union
(when required)

Capacity of pipe for pipe size of:
(Capacity in cubic feet gas per hour)

Gas pipe
length
(feet)

½"

¾"

1¼"

1½"

132

278

520

1050

1600

190

350

730

1100

152

285

590

860

Nipple

130

245

500

760

Cap

115

215

440

670

175

360

545

100

150

305

460

150

120

250

380

Tee

59322

Part Number 550-110-593/1099

Boiler Manual

Field wiring
For your safety, turn off electrical power supply at
service entrance panel before making any electrical
connections to avoid possible electric shock hazard.
Failure to do so can cause severe personal injury or
death.
Wiring must be N.E.C. Class 1.

If rollout thermal fuse element wire as supplied with
boiler must be replaced, type 200 °C wire or equivalent
must be used. If other original wiring as supplied with
boiler must be replaced, use only type 105 °C wire or
equivalent.
Boiler must be electrically grounded as required by
National Electrical Code ANSI/NFPA 70-latest edition.

Electrical installation must
comply with:
1. National Electrical Code and any other national,
state, provincial or local codes or regulations.
2. In Canada, CSA C22.1 Canadian Electrical Code
Part 1, and any local codes.

Wiring connections
Boiler is shipped with controls completely wired, except
spill switch and vent damper. Refer to wiring diagrams
shown on page 34 for standing pilot ignition boiler or
page 38 for spark-ignited pilot boiler.

Figure 20
Field wiring

Field wiring connections —
service switch and
thermostat (or end switch)
provided by installer

120 VAC
Hot

Thermostat
1. Connect thermostat as shown on wiring diagram
on boiler.
2. Install on inside wall away from influences of drafts,
hot or cold water pipes, lighting fixtures, television,
sunrays or fireplaces.
3. If thermostat has a heat anticipator, set heat
anticipator in thermostat to match power
requirements of equipment connected to it. If
connected directly to boiler, set for 0.1 amps plus
gas valve current. See information on the wiring
diagram shown in Figure 25b, page 39. For other
devices, refer to manufacturer’s specifications.
Wiring diagram on boiler gives setting for control
module and gas valve. Also see instructions with
thermostat.
Junction box (furnished)
1. Connect 120 VAC power wiring (Figure 20).
2. Fused disconnect or service switch (15 amp.
recommended) may be mounted on this box. For
those installations with local codes which prohibit
installation of fused disconnect or service switch on
boiler, install a 2 x 4 cover plate on the boiler
junction box and mount the service switch remotely
as required by the code.
Wiring multiple zones
Refer to zone valve manufacturer’s literature for wiring
and application. A separate transformer is required to
power zone valves. Zoning with circulators requires a
relay for each circulator.

Service
switch
Neutral

Ground

(not provided)

Thermostat
or end switch
(not provided)

Service
switch
(not provided)

Thermostat
or end switch

Factory wiring

Ground screw

Black

White

Green

Wire nuts

Black

(not provided)

Black

Thermostat
leads, through
jacket left side

Junction box,
boiler left side
59323

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Start-up — preparation
Check for gas leaks
Before starting the boiler, and during initial operation, smell near the floor and around the
boiler for gas odorant or any unusual odor. Do not proceed with start-up if there is any indication
of a gas leak. Repair any leak at once.
Propane boilers only — Your propane supplier mixes an odorant with the propane to make
its presence detectable. In some instances, the odorant can fade and the gas may no longer have
an odor.
• Propane gas can accumulate at floor level. Smell near the floor for the gas odorant or any
unusual odor. If you suspect a leak, do not attempt to light the pilot.
• Use caution when attempting to light the propane pilot. This should be done by a qualified
service technician, particularly if pilot outages are common.
• Periodically check the odorant level of your gas.
• Inspect boiler and system at least yearly to make sure all gas piping is leak-tight.
• Consult your propane supplier regarding installation of a gas leak detector. There are some
products on the market intended for this purpose. Your supplier may be able to suggest an
appropriate device.

Determine if water treatment is needed
Do not use petroleum-based cleaning or sealing compounds in boiler system. Severe damage
to boiler will occur, resulting in substantial property damage.
Eliminate all system leaks. Continual fresh makeup water will reduce boiler life. Minerals can
build up in sections, reducing heat transfer, overheating cast iron, and causing section failure.
Verify water chemistry
Consult local water treatment companies for unusually hard water areas (above 7 grains
hardness) or low pH water conditions (below 7.0). Boiler water pH of 7.0 to 8.5 is recommended.
Freeze protection (when used)
Use antifreeze made especially for hydronic systems. Inhibited propylene glycol is recommended.
Do not use ethylene glycol, automotive or undiluted antifreeze. Severe personal injury or
death can result.
1. Determine antifreeze quantity according to system water content. Boiler water content is
listed on page 67. Remember to include expansion tank water content.
2. Follow antifreeze manufacturer's instructions.
3. A 50% solution of propylene glycol/water provides maximum protection to about -30 °F.
4. Local codes may require back flow preventer or actual disconnect from city water supply.
5. When using antifreeze in a system with automatic fill, install a water meter to monitor
water makeup. Glycol will leak before the water begins to leak, causing glycol level to drop.
Added water will dilute the antifreeze, reducing the freeze protection level.
28

Part Number 550-110-593/1099

Boiler Manual

Fill the system with water
1. Close manual and automatic air vents and boiler drain cock.
2. Fill to correct system pressure. Correct pressure will vary with each application. Typical
cold water fill pressure for a residential system is 12 psi.
3. Purge air from system:
a. Connect a hose to the purge valve (see drain valves, item 6, in suggested piping diagrams
on pages 17 through 23, Figure 9 through Figure 16). Route hose to an area where
water can drain and be seen.
b. Close the boiler or system isolation valve between the purge valve and fill connection
to the system.
c. Close zone isolation valves.
d. Open quick-fill valve on cold water makeup line.
e. Open purge valve.
f. One zone at a time, open the isolation valves. Allow water to run through the zone,
pushing out the air. Run until no noticeable air flow is present. Close the zone isolation
valves and proceed with the next zone. Follow this procedure until all zones are purged.
g. Close the quick-fill water valve and purge valve and remove the hose. Open all isolation
valves. Watch that system pressure rises to correct cold-fill pressure.
h. After the system has operated for a while, eliminate any residual air by using the manual
air vents located throughout the system.
i. If purge valves are not installed in system, open manual air vents in system one at a
time, beginning with lowest floor. Close vent when water squirts out. Repeat with
remaining vents.
4. Open automatic air vent (diaphragm-type or bladder-type expansion tank systems only)
one turn.
5. Open other vents:
a. Starting on the lowest floor, open air vents one at a time until water squirts out.
b. Repeat with remaining vents.
6. Refill to correct pressure.

Inspect system water piping
After filling the boiler and system with water, inspect all piping throughout the system for
leaks. If found, repair immediately. Repeat this inspection after the boiler has been started and
the system has heated up.
Leaks must be repaired at once. Failure to do so can damage the 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.
Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Start-up — preparation

continued

Inspect base insulation
The boiler contains ceramic fiber and fiberglass materials. Use care when
handling these materials per instructions on page 68 of this manual. Failure
to comply could result in severe personal injury.
Failure to replace damaged insulation or reposition insulation can result

in a fire hazard, causing severe personal injury, death or substantial property
damage.
Check to make sure insulation is secure against all four sides of the base. If insulation is
damaged or displaced, do not operate boiler. Replace or reposition insulation.

Start-up — operate boiler
DO NOT proceed with boiler operation unless boiler and system have been

filled with water and all instructions and procedures of previous manual
sections have been completed. Failure to do so could result in severe personal
injury, death or substantial property damage. Before starting the boiler . . .
•

Read manual Section 8/9 and the Lighting/Operating instruction
procedure (see Table 5, below).

•

Verify the boiler and system are full of water.

•

Verify the Start-up preparation procedures of Section 6 have been
completed.

Table 5 Lighting/Operating instruction location guide
Models Standing pilot
CGa-25
to
CGa-6
CGa-7
to
CGa-8

Gas

Page Spark-ignited pilot

Natural or
Honeywell VR8200/VR8300
Propane

Robertshaw 7200

Natural

Gas

Page

Honeywell VR8204/VR8304 Natural

Robertshaw 7200

Natural

White-Rodgers 36E

Natural

Natural or
Honeywell VR8200/VR8300
Propane

Honeywell VR8204/VR8304 Natural

Robertshaw 7200

White-Rodgers 36C

Natural

Part Number 550-110-593/1099

Boiler Manual

Start-up — operate boiler

continued

Start the boiler
•

Follow the Lighting/Operating Instructions from
Section 8 or 9 to start the boiler. Remove boiler
jacket door and note the gas valve manufacturer and
model number. Use only the lighting/operating
instruction which applies to this gas valve (see Table

5, page 30). (The lighting instruction label on the
boiler provides the same information.)

•

See Section 6c, below, if boiler fails to start.

Check system and boiler
Eliminate all system leaks. Continual fresh makeup

water will reduce boiler life. Minerals can build up in
sections, reducing heat transfer, overheating cast iron,
and causing section failure.
If you discover evidence of any gas leak, shut down the
boiler at once. Find the leak source with bubble test and
repair immediately. Do not start boiler again until
corrected. Failure to comply could result in severe
personal injury, death or 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.
1. Check system piping for leaks. If found, shut down
boiler and repair immediately.

2. Vent air from system using manual vents. Air in
the system will interfere with circulation and cause
heat distribution problems and noise.
3. Inspect vent system thoroughly for signs of
deterioration from corrosion, physical damage or
sagging. Verify that masonry chimney liners are in
good condition, with no obstructions, and there are
no openings into the chimney.
4. Check around the boiler for gas odor following the
procedure of section 6a, page 28 of this manual.
5. Verify operation per section 6d, page 32. Perform
check-out procedure in section 7, page 33, and fill
in the Installation and service certificate.

Start-up — if boiler doesn’t start . . .
Check for:
1. Loose connections, blown fuse or service switch off?

4. Gas not turned on at meter or boiler?

2. High limit switch set below boiler water temperature?

5. Incoming gas pressure less than:
5" w.c. for natural gas? 11" w.c. for propane gas?

3. Thermostat set below room temperature?

6. If none of the above corrects the problem, refer to
Troubleshooting, section 11, page 49 of this manual.

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Start-up — verify operation
The boiler model suffix will be “SPD”. For spark-ignited
pilot boilers (suffix “PID”), see Section 8 or 9 for
operation and lighting/operating information.

Figure 21

Typical pilot burner flame

Figure 22

Typical main burner flame

Part Number 550-110-593/1099

Boiler Manual

Check-out procedure — checklist

❏

Boiler and heat distribution units filled with water?

❏

Automatic air vent, if used, open one full turn?

❏

Air purged from system?

❏

Air purged from gas piping? Piping checked for leaks?

❏

Correctly sized manifold orifices installed? Refer to Table 2,
page 12 to check size and fuel type.

❏

Open manual main shutoff gas valve. Manometer
should confirm there is no gas flow. Pilot will relight,
flame sensing element will sense pilot flame and main
burners reignite.
Set limit control(s) to system temperature requirements.
Adjust balancing valves and controls to provide design
temperature to system.

❏

Correctly sized manifold orifices must be used.
Failure to do so will cause severe personal
injury, death or substantial property damage.

For multiple zones, adjust flow so it is about the same in
each zone.

❏

Followed lighting/operating instructions on boiler or in
manual section 8, page 34 or section 9, page 37 for proper
start-up?

Verify thermostat heat anticipator (if available) set properly?
Refer to Field wiring , manual section 5 , page 27,
Thermostat(s).

❏

Cycle boiler with thermostat — Raise to highest setting and
verify boiler goes through normal start-up cycle. Lower to
lowest setting and verify boiler goes off.

❏

Measure natural gas input:
a. Operate boiler 10 minutes.
b. Turn off other appliances.
c.
At natural gas meter, measure time (in seconds)
required to use one cubic foot of gas.
d. Calculate gas input:

❏

Proper burner flame observed? Refer to Check burner flame,
manual section 6d, page 32.

❏

Test limit control — While burners are operating, move
indicator on limit control below actual boiler water
temperature. Burners should go off while circulator
continues to operate. Raise setting on limit control above
boiler water temperature and burners should reignite.

❏

Test additional field-installed controls — If boiler has a low
water cutoff, additional high limit or other controls, test for
operation as outlined by manufacturer. Burners should be
operating and should go off when controls are tested. When
controls are restored, burners should reignite.

❏

Botton on spill switch pushed in?

❏

Test ignition system safety device:
a. Standing pilot — Turn gas cock knob to PILOT
position and extinguish pilot flame. Pilot gas flow
should stop in less than 3 minutes. Put system back
into operation (see section 6, pages 28-32).
b. Spark-ignited pilot — Connect manometer to outlet
side of gas valve. Start boiler, allowing for normal startup cycle to occur and main burners to ignite. With
main burners on, manually shut off gas supply at
manual main shutoff gas valve. Burners should go off.

3600 x 1000
= Btuh
number of seconds from step c

e.
❏

Btuh calculated should approximate input rating on
boiler rating label.
Check manifold gas pressure by connecting manometer to
downstream test tapping on main gas valve. Manifold
pressure for natural gas should be 3.5" w.c. and for propane
gas should be 10" w.c.

❏

Observe several operating cycles for proper operation.

❏

Set room thermostat to desired room temperature.

❏

Fill in Installation and service certificate below?

❏

Review all instructions shipped with this boiler with owner
or maintenance person. Return instructions to envelope and
give to owner or place in pocket inside front panel in boiler.

Installation and service certificate
Boiler model __________________
Measured Btuh input ____________

Installer ________________________
(company)

Series __________
❏
❏
❏
❏

CP number ___________

Date installed _______________

Installation instructions have been followed.
Check out sequence has been performed.
Above information is certified to be correct.
Information received and left with owner/maintenance person

________________________________
(address)

______________________________
(phone)
_____________________________________
(installer’s signature)

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Figure 23

Operation — standing pilot boilers

Wiring diagram — Standing pilot system

LADDER WIRING DIAGRAM

SCHEMATIC WIRING DIAGRAM
H

ADDITIONAL
LIMITS
(NOTE 6)
BK
EQUIPMENT
GROUND
(NOTE 7)

ROLLOUT
TFE

G
C
BK

24 V.A.C.

THERMOSTAT
OR EMCS
(NOTE 5)

RELAY COIL
CR

TRANSFORMER
120/24 V.A.C.

CABLE
TO
DAMPER

W
Y

PLUG-IN
DPST
RELAY

PRIMARY

CIRCULATOR

CR2
DAMPER
CONNECTOR

Y
G

THERMOSTAT
OR EMCS
(NOTE 5)

THERMOCOUPLE

GAS
VALVE

PILOT

CIRCULATOR

EQUIPMENT
GROUND
(NOTE 7)

SERVICE SWITCH
(BY OTHERS)

SERVICE
SWITCH
(BY OTHERS)

N
120 V.A.C.

CABLE
TO
DAMPER

LIMIT
CONTROL

SPILL
SWITCH

JUNCTION BOX

ELECTRICAL SHOCK HAZARD, CAN CAUSE SEVERE
INJURY OR DEATH. DISCONNECT POWER
BEFORE INSTALLING AND/OR SERVICING.

ADDITIONAL
LIMIT
LIMITS
SPILL
(NOTE 6) SWITCH CONTROL

4
DAMPER
CONNECTOR

FUSE

CR1

WIRE NUT

ROLLOUT
TFE

NOTES:
1. ALL WIRING MUST BE INSTALLED IN ACCORDANCE WITH:
A. U.S.A. - NATIONAL ELECTRICAL CODE AND ANY OTHER NATIONAL, STATE OR LOCAL
CODE REQUIREMENTS.
B. CANADA - C.S.A. C22.1 CANADIAN ELECTRICAL CODE PART 1 AND ANY OTHER
NATIONAL, PROVINCIAL OR LOCAL CODE REQUIREMENTS.
2. ALL CONTACTS SHOWN WITHOUT POWER APPLIED-OFF SHELF CONDITION.
3. IF ORIGINAL ROLLOUT TFE WIRE AS SUPPLIED WITH THE APPLIANCE MUST BE REPLACED,
TYPE 200 o C WIRE OR ITS EQUIVALENT MUST BE USED. IF OTHER ORIGINAL WIRE AS
SUPPLIED WITH THE APPLIANCE MUST BE REPLACED, TYPE 105 oC OR ITS EQUIVALENT MUST
BE USED.

4. REFER TO CONTROL COMPONENT INSTRUCTIONS PACKED WITH BOILER FOR APPLICATION INFORMATION.
5. THERMOSTAT - FOR SINGLE ZONE SYSTEMS, THERMOSTAT ANTICIPATOR SETTING IS 0.40 AMPS.
FOR MULTIPLE ZONE SYSTEMS USING ZONE VALVES OR CIRCULATORS, REFER
TO COMPONENT MANUFACTURER’S INSTRUCTIONS FOR
APPLICATION WIRING AND THERMOSTAT ANTICIPATOR SETTING.
EMCS - FOR EMCS CONNECTION IN PLACE OF THERMOSTAT, REFER TO
EMCS INSTALLATION/OPERATING MANUAL.
6. L.W.C.O., ADDITIONAL HIGH LIMIT, ETC., WIRED IN SERIES.
7.

DENOTES FIELD INSTALLED CHASSIS GROUND.

CGa
25 thru 8

LOW VOLTAGE FIELD
HIGH VOLTAGE FIELD
LOW VOLTAGE FACTORY
HIGH VOLTAGE FACTORY
THERMOCOUPLE

Standing Pilot

A United Dominion Company

Natural Or Propane Gas
Weil-McLain

500 Blaine St.

Forced Hot Water
PART NUMBER

Michigan City, IN 46360-2388

550-225-009/0999

Part Number 550-110-593/1099

Boiler Manual

8b Lighting instructions — CGa-25 to CGa-8
FOR YOUR SAFETY READ BEFORE LIGHTING
If you do not follow these instructions exactly, a fire or explosion may result
causing property damage, personal injury or loss of life.
A. This appliance has a pilot, which must be lighted
by hand. When lighting the pilot, follow these
instructions exactly.
B. Before LIGHTING, smell all around the appliance
area for gas. Be sure to smell next to the floor
because some gas is heavier than air and will settle
on the floor. See below.

C. Use only your hand to push down the reset button or turn the gas
control knob. Never use tools. If the knob or reset button will not
operate by hand, don't try to repair it, call a qualified service technician.
Force or attempted repair may result in a fire or explosion.
D. Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect the appliance
and to replace any part of the control system and any gas control,
which has been under water.

WHAT TO DO IF YOU SMELL GAS

•

Do not try to light any appliance.

•

Do not touch any electric switch; do not use any phone in
your building.

Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.

•

If you cannot reach your gas supplier, call the fire
department.

LIGHTING INSTRUCTIONS
1. Stop! Read the safety information above on this label.
2. Set the thermostat to lowest setting.
3. When equipped with Effikal vent damper Model RVGP,
place service switch in Hold Damper Open position.
4. Turn off all electrical power to the appliance.
5. When equipped with Johnson Controls vent damper
Model M35, manually rotate damper blade in direction of
arrow to Open position indicated on damper assembly.
to OFF.
6. Turn gas control knob clockwise
7. When equipped with vent damper, verify damper blade is
in full open position.

8. Wait five (5) minutes to clear out any gas. Then smell for
gas, including near the floor. If you smell gas, STOP! Follow
"B" in the safety information above. If you don't smell gas,
go to the next step.

9. Remove access panel located above burners.
10. Find pilot — follow metal tube from gas
control. The pilot is between two burners
behind the access panel.
11. Turn gas control knob counterclockwise
to PILOT.
12. Push in red reset button and hold. Immediately light the
pilot with a match. Continue to hold reset button in for
about one (1) minute after the pilot is lit.
13. Release reset button. Pilot should remain lit. If pilot goes
out, repeat steps 6 through 13.
• If reset button stays depressed after release, stop and
immediately call your service technician or gas supplier.
• If the pilot will not stay lit after several tries, turn the
gas control knob clockwise
to OFF and call your
service technician or gas supplier.
14. Replace access panel.
to ON.
15. Turn gas control knob counterclockwise
16. Turn on all electric power to the appliance.
17. When equipped with Effikal vent damper, place service
switch in Automatic Operation position.
18. Set thermostat to desired setting.
19. Replace front panel.

TO TURN OFF GAS TO THE APPLIANCE
1. Set the thermostat to lowest setting.

3. Remove front panel.

2. Turn off all electric power to the appliance if service is to
be performed.

4. Turn gas control knob clockwise

Part Number 550-110-593/1099

to OFF.

5. Replace front panel.
35

GOLD CGa Gas-Fired Water Boiler

8b Lighting instructions — CGa-25 to CGa-8
• Standing pilot

• Gas valve manufacturer — Robertshaw

• Natural gas

• Gas valve model(s) — 7200

FOR YOUR SAFETY READ BEFORE LIGHTING
If you do not follow these instructions exactly, a fire or explosion may result
causing property damage, personal injury or loss of life.
A. This appliance has a pilot, which must be lighted
by hand. When lighting the pilot, follow these
instructions exactly.
B. Before LIGHTING, smell all around the appliance
area for gas. Be sure to smell next to the floor
because some gas is heavier than air and will settle
on the floor. See below.

C. Use only your hand to depress the selector arm. Never use tools. If the
selector arm will not move by hand, don't try to repair it, call a qualified
service technician. Force or attempted repair may result in a fire or
explosion.
D. Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect the appliance
and to replace any part of the control system and any gas control,
which has been under water.

WHAT TO DO IF YOU SMELL GAS

•

Do not try to light any appliance.

•

Do not touch any electric switch; do not use any phone in
your building.

Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.

•

If you cannot reach your gas supplier, call the fire
department.

LIGHTING INSTRUCTIONS
1. Stop! Read the safety information above on this label.
2. Set the thermostat to lowest setting.
3. When equipped with Effikal vent damper Model RVGP,
place service switch in Hold Damper Open position.
4. Turn off all electrical power to the appliance.
5. When equipped with Johnson Controls vent damper
Model M35, manually rotate damper blade in direction of
arrow to Open position indicated on damper assembly.
to OFF.
6. Depress and move selector arm left
7. When equipped with vent damper, verify damper blade is
in full open position.
Position
indicator

Selector
arm

(shown in
OFF position)
59332

9. Remove access panel located above burners.
10. Find pilot — follow metal tube from gas
control. The pilot is between two burners
behind the access panel.
11. Move selector arm on gas control right
to SET position.
12. Hold selector arm in SET position and immediately light
the pilot with a match. Continue to hold selector arm to
SET for about one-half (¹⁄₂) minute after the pilot is lit.
13. Release selector arm. If pilot does not remain lit, repeat steps
6 through 13.
• If the pilot will not stay lit after several tries, move
to OFF and call your service
selector arm left
technician or gas supplier.
14. Replace access panel.
15. Turn selector arm left
to ON.
16. Turn on all electric power to the appliance.
17. When equipped with Effikal vent damper, place service
switch in Automatic Operation position.
18. Set thermostat to desired setting.
19. Replace front panel.

TO TURN OFF GAS TO THE APPLIANCE
1. Set the thermostat to lowest setting.

3. Remove front panel.

2. Turn off all electric power to the appliance if service is to
be performed.

4. Depress and move selector arm left

to OFF.

5. Replace front panel.

Part Number 550-110-593/1099

Boiler Manual

Operation — spark-ignited pilot boilers
Follow all procedures given in this manual and operating
instructions when operating the boiler. Failure to do so
could result in severe personal injury, death or
substantial property damage.
1. Standby: With no call for heat, the vent damper and
circulator are deenergized. No gas flows to pilot or main
gas valve.
2. Call for heat (thermostat circuit closes):
a. Vent damper and circulator energized if pilot status
acceptable. Vent damper drives open. When vent
damper end switch makes circuit, ignition control
begins pilot ignition attempt.
b. Ignition control checks for false flame signal: If
ignition control senses pilot signal when no pilot
gas should be present, control will lockout,
requiring reset procedure as given in Figure 24.
3. Pilot ignition: Control module sparks the pilot and
opens pilot valve in main gas valve.
a. If pilot does light and control module senses flame
current, spark generator is turned off and main
valve opens.
b. If pilot does not light within 15 seconds, pilot valve

Figure 24

is closed and spark generator is turned off. Control
module waits 5 minutes, then attempts to ignite
pilot again. This cycle will continue indefinitely if
pilot ignition control does not sense pilot flame.
4. Main burner operation:
a. Control module monitors pilot flame current. If
signal is lost, main valve closes, spark generator
activates and sequence returns to step 4.
b. If power is interrupted, control system shuts off
pilot and main gas valves and restarts at step 1 when
power is restored.
c. In the event the limit control shuts down the boiler
— The control module closes the main gas valve,
but keeps the circulator operating and the vent
damper open.
5. Thermostat satisfied (thermostat circuit opens) —
Pilot and main gas valves are closed — Vent damper is
deenergized, and cycles to closed position. Circulator
is shut off.
6. Boiler is now in the standby mode.
7. Thermostat anticipator setting: Set thermostat heat
anticipator as instructed in Figure 25b, page 39.

Ignition control module sequence of operation — status light indications

Steps

Call for
heat?

POWER

TSTAT
CIRC

LIMIT

DAMPER

FLAME

Timing

(Following step 7, cycle goes back to step 1.)

1. Standby
·
Waiting for call for heat

—

2. Call for heat
·
Circulator on

YES

—

3. Limit circuit
·
Limit controls closed

YES

—

4. Damper circuit
·
Damper proven open

YES

—

5. Pilot flame proven *
·
Gas valve open
·
Pilot remains on
·
Boiler producing heat

YES

6. Limit cycle
·
Limit circuit open
·
Gas valve closed

YES

—

7. Flame outage *
·
Flame out
·
Boiler recycles

YES

—

8. Thermostat satisfied
·
Circulator off

15 sec

9. Circulator exercise routine
·
Circulator turns on for 30 seconds
if boiler not operated for 30 days

30 sec

15 sec

= "ON"

= "OFF"

* If pilot flame is not proven in 15 seconds, control module will flash the FLAME light, but will continue indefinitely with attempts to light the pilot burner.
The control module will not lockout on a failure to establish flame. It will lockout if line voltage polarity is reversed, stray voltage is sensed on thermostat
line, or if flame is sensed when it shouldn’t be there.
The boiler will reset after these lockouts if any of the following occurs:
• 1 hour waiting period
• Opening and closing of thermostat circuit
• Removal of 120 VAC power for at least 45 seconds.
59340

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

Operation — spark-ignited pilot system continued

Figure 25a

Schematic wiring diagram — Spark-ignited pilot system

White Plug-in
Red connectors

OFF
ON

Part Number 550-110-593/1099

Boiler Manual

Figure 25b

Ladder wiring diagram — Spark-ignited pilot system

Electrical shock hazard — can cause
severe injury or death. Disconnect
power before installing or servicing.

Hot

Neutral

Gnd

120 VAC

SERVICE
SWITCH

Legend for ladder wiring diagram
120 VAC field wiring
Low voltage field wiring

HIGH
VOLTAGE

120 VAC factory wiring
Low voltage factory wiring
High voltage spark ignition wiring
Ground connectors

PILOT
IGNITION
ELECTRODE

CONTROL
MODULE
120 VAC
SECTION

120 VAC

Table G: Gas valve terminals and anticipator settings
Gas valve

"A"

Honeywell VR8204

"B"

"C"

PV
MV/PV MV
Honeywell VR8304 MV/PV MV
PV
Robertshaw 7200
P
M
C
White-Rodgers 36C 2–4 *
3
1
* Terminals 2–4 are factory-jumpered on the
White-Rodgers 36C gas valve.

Anticipator
amps

0.6
0.8
0.55
0.7

1. All wiring must be installed in accordance with:
A. U.S.A. — N.E.C. And any other national, state,
or local code requirements.
B. Canada — C.S.A. C22.1 C.E.C. Part 1 and any
other national, provincial, or local code requirements.
2. Pilot lead wires are not field replaceable. Replace pilot assembly if necessary.
3. If any of the original wire as supplied with the appliance must be replaced, use minimum 105 °C
wire or equivalent. Exception — wires to a rollout
TFE must be 200 °C or equivalent.
4. Thermostat anticipator setting (single zone) — see
Table G for anticipator setting, depending on
which gas valve is installed in boiler.
5. For multiple zoning, use either zone valves or
circulators. Refer to the component manufacturer's instructions and this manual for application and wiring suggestions.
6. Refer to control component instructions packed
with the boiler for application information.
7. Wire any additional limit controls (low water cutoff, additional high limit, etc.) in series with boiler
limit control as shown.
Part Number 550-110-593/1099

CIRCULATOR

24 VAC

G POWER

THERMOSTAT
R TSTAT/CIRC
Additional
limits
(note 7)

24VAC
CONSTANT

VENT
DAMPER
24VAC
CALL FOR
HEAT

SPILL
SWITCH
R LIMIT

ROLLOUT
TFE

WATER
TEMPERATURE
LIMIT SWITCH

CONTROL MODULE
LOW VOLTAGE
SECTION

PILOT GAS
VALVE
"C"
"A"

R DAMPER
DAMPER END SWITCH
(INTERNAL TO DAMPER)
HIGH
VOLTAGE
PILOT
FLAME
SENSOR
59347a

R FLAME

"B"
MAIN GAS
VALVE
See Table G

GOLD CGa Gas-Fired Water Boiler

FOR YOUR SAFETY READ BEFORE OPERATING
If you do not follow these instructions exactly, a fire or explosion may result
causing property damage, personal injury or loss of life.
A. This appliance is equipped with an ignition device
which automatically lights the pilot. Do not try to
light the pilot by hand.
B. Before OPERATING , smell all around the
appliance area for gas. Be sure to smell next to the
floor because some gas is heavier than air and will
settle on the floor. See below.

C. Use only your hand to turn the gas control knob. Never use tools. If
the knob will not turn by hand, don't try to repair it, call a qualified
service technician. Force or attempted repair may result in a fire or
explosion.
D. Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect the appliance
and to replace any part of the control system and any gas control,
which has been under water.

WHAT TO DO IF YOU SMELL GAS

•

Do not try to light any appliance.

•

Do not touch any electric switch; do not use any phone in
your building.

Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.

•

If you cannot reach your gas supplier, call the fire
department.

OPERATING INSTRUCTIONS
1. Stop! Read the safety information above on this label.
2. Set the thermostat to lowest setting.
3. When equipped with Effikal vent damper Model RVGP,
place service switch in Hold Damper Open position.
4. Turn off all electrical power to the appliance.
5. When equipped with Johnson Controls vent damper
Model M35, manually rotate damper blade in direction of
arrow to Open position indicated on damper assembly.
6. This appliance is equipped with an ignition device which
automatically lights the pilot. Do not try to light the pilot
by hand.
7. Turn gas control knob clockwise

to OFF.

10. Turn gas control knob counterclockwise
11. Turn on all electric power to the appliance.

12. When equipped with Effikal vent damper, place service
switch in Automatic Operation position.
13. Set thermostat to desired setting.
14. If the appliance will not operate, follow the instructions To
Turn Off Gas To The Appliance and call your service
technician or gas supplier.
15. Replace front panel.

TO TURN OFF GAS TO THE APPLIANCE
1. Set the thermostat to lowest setting.
2. Turn off all electric power to the appliance if service is to
be performed.

4. Turn gas control knob clockwise
force.

to OFF. Do not

5. Replace front panel.

3. Remove front panel.
40

Part Number 550-110-593/1099

Boiler Manual

9b Operating instructions — CGa-25 to CGa-6
• Spark pilot

• Gas valve manufacturer — Robertshaw

• Natural gas

• Gas valve model(s) — 7200

C. Use only your hand to depress or move the selector arm. Never use
tools. If the selector arm will not depress or move by hand, don't try
to repair it, call a qualified service technician. Force or attempted repair
may result in a fire or explosion.
D. Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect the appliance
and to replace any part of the control system and any gas control,
which has been under water.

WHAT TO DO IF YOU SMELL GAS

•

Do not try to light any appliance.

•

Do not touch any electric switch; do not use any phone in
your building.

Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.

•

If you cannot reach your gas supplier, call the fire
department.

8. When equipped with vent damper, verify damper blade is
in full open position.
9. Wait five (5) minutes to clear out any gas. Then smell for
gas, including near the floor. If you smell gas, STOP! Follow
"B" in the safety information above. If you don't smell gas,
go to the next step.
10. Move selector arm to ON.
11. Turn on all electric power to the appliance.
12. When equipped with Effikal vent damper, place service
switch in Automatic Operation position.
13. Set thermostat to desired setting.

Position
indicator

Selector
arm

(shown in
OFF position)

14. If the appliance will not operate, follow the instructions To
Turn Off Gas To The Appliance and call your service
technician or gas supplier.
15. Replace front panel.

59332

TO TURN OFF GAS TO THE APPLIANCE
1. Set the thermostat to lowest setting.

4. Depress and move selector arm to OFF. Do not force.

2. Turn off all electric power to the appliance if service is to
be performed.

5. Replace front panel.

3. Remove front panel.
Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

WHAT TO DO IF YOU SMELL GAS

•

Do not try to light any appliance.

•

Do not touch any electric switch; do not use any phone in
your building.

Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.

•

If you cannot reach your gas supplier, call the fire
department.

to OFF.

10. Turn gas control knob counterclockwise
11. Turn on all electric power to the appliance.

12. When equipped with Effikal vent damper, place service
switch in Automatic Operation position.
13. Set thermostat to desired setting.

Position
indicator

Gas
control
knob

(shown in
ON position)

14. If the appliance will not operate, follow the instructions To
Turn Off Gas To The Appliance and call your service
technician or gas supplier.
15. Replace front panel.

59333

TO TURN OFF GAS TO THE APPLIANCE
1. Set the thermostat to lowest setting.
2. Turn off all electric power to the appliance if service is to
be performed.

4. Turn gas control knob clockwise
force.

to OFF. Do not

5. Replace front panel.

3. Remove front panel.
42

Part Number 550-110-593/1099

Boiler Manual

C. Use only your hand to depress or turn the gas control knob. Never
use tools. If the knob will not depress or turn by hand, don't try to
repair it, call a qualified service technician. Force or attempted repair
may result in a fire or explosion.
D. Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect the appliance
and to replace any part of the control system and any gas control,
which has been under water.

WHAT TO DO IF YOU SMELL GAS

•

Do not try to light any appliance.

•

Do not touch any electric switch; do not use any phone in
your building.

Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.

•

If you cannot reach your gas supplier, call the fire
department.

to ON.

11. Turn on all electric power to the appliance.
12. When equipped with Effikal vent damper, place service
switch in Automatic Operation position.
13. Set thermostat to desired setting.
14. If the appliance will not operate, follow the instructions To
Turn Off Gas To The Appliance and call your service
technician or gas supplier.
15. Replace front panel.

TO TURN OFF GAS TO THE APPLIANCE
1. Set the thermostat to lowest setting.
2. Turn off all electric power to the appliance if service is to
be performed.

4. Depress gas control knob slightly and turn clockwise
to OFF. Do not force.
5. Replace front panel.

3. Remove front panel.
Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

10a

Service and maintenance — schedule
Table 6

Service and maintenance schedules (service technician and user)

Service technician

Owner maintenance

(see following pages for instructions)

(see CGa User’s Information Manual for instructions)

• Check boiler area

Inspect:
• Reported problems

Daily

• Check air openings
• Check boiler pressure/
temperature gauge

• Boiler area
• Air openings
• Flue gas vent system

• Check boiler interior piping

• Pilot and main burner flames

• Check venting system

• Water piping

ANNNUAL START-UP

Monthly
• Boiler heating surfaces

• Check air vents
• Check boiler relief valve

• Burners and base

• Check automatic air vents (if
used)

Service:
• Oiled-bearing circulators

Start-up:

Periodically

• Test low water cutoff (if used)

• Perform start-up per manual

Check/test:

Every 6 months

• Operate relief valve

End of season

• Shut down procedure

• Gas piping
• Cold fill and operating pressures
• Air vents and air elimination
• Limit controls and cutoffs
• Expansion tank
• Boiler relief valve

Review:
• Review with owner

Follow the Service and maintenance procedures given throughout this manual and in component literature
shipped with the boiler. Failure to perform the service and maintenance could result in damage to the boiler or
system. Failure to follow the directions in this manual and component literature could result in severe personal
injury, death or substantial property damage.
44

Part Number 550-110-593/1099

Boiler Manual

10b

Service & maintenance — annual start-up
The boiler should be inspected and started annually, at the beginning of the heating season, only by a qualified
service technician. In addition, the maintenance and care of the boiler designated in Table 6 and explained on the
following pages must be performed to assure maximum boiler efficiency and reliability. Failure to service and
maintain the boiler and system could result in equipment failure.

❏

Inspect . . . . . . . . . .

2. Verify that boiler vent discharge and air intake are
clean and free of obstructions.

Reported problems

Flue gas vent system

Inspect any problems reported by owner and correct
before proceeding.

1. Visually inspect entire flue gas venting system
for blockage, deterioration or leakage. Repair any
joints that show signs of leakage in accordance with
vent manufacturer’s instructions.

Boiler area
1. Verify that boiler area is free of any combustible
materials, gasoline and other flammable vapors and
liquids.
2. Verify that boiler area (and air intake) is free of any
of the contaminants listed in Table 1 on page 9 of
this manual. If any of these are present in the boiler
intake air vicinity, they must be removed. If they
cannot be removed, install combustion air piping
to the boiler in accordance with national, provincial
or local codes.

Air openings
1. Verify that combustion and ventilation air openings
to the boiler room and/or building are open and
unobstructed . Check operation and wiring of
automatic combustion air dampers, if used.

2. Verify that masonry chimneys are lined, lining is in
good condition, and there are not openings into the
chimney.
Failure to inspect for the above
conditions and have them repaired
can result in severe personal injury
or death.

Pilot and main burner flames
1. Visually inspect pilot burner and main burner
flames as directed under section 6d, page 32 of this
manual.

Water piping
1. Check the boiler interior piping and all system
piping for signs of leaks.
2. Repair any leaks before proceeding.

The boiler contains ceramic fiber and fiberglass materials. Use care when handling these
materials per instructions on page 68 of this manual. Failure to comply could result in severe
personal injury.

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

10b
❏

Service & maint. — annual start-up
Inspect . . . . . . . . . .
Electrical shock hazard — Turn off power to the boiler
before any service operation on the boiler except as
noted otherwise in this instruction manual. Failure to
turn off electrical power could result in electrical shock,
causing severe personal injury or death.
Do not use petroleum-based cleaning or sealing
compounds in boiler system. Severe damage to boiler
will occur, resulting in substantial property damage.
Eliminate all system or boiler leaks. Continual fresh

makeup water will reduce boiler life. Minerals can build
up in sections, reducing heat transfer, overheating cast
iron, and causing section failure. Leaking water may also
cause severe property damage.

Boiler heating surfaces
1. Disconnect the vent pipe at the boiler draft hood
and remove draft hood after turning off power to
the boiler.
2. Use a bright light to inspect the boiler flue collector
and heating surfaces.
3. If the vent pipe or boiler interior surfaces show
evidence of soot, follow Cleaning boiler heating
surfaces in this manual section. Remove the flue
collector and clean the boiler if necessary after closer
inspection of boiler heating surfaces.
4. If there is evidence of rusty scale deposits on boiler
surfaces, check the water piping and control system
to make sure the boiler return water temperature is
properly maintained (per this manual).
5. Reconnect vent and draft hood. Replace all boiler

continued

components before returning to service.
6. Check inside and around boiler for evidence of any
leaks from the boiler. If found, locate source of leaks
and repair.

Burners and base
1. After turning off power to the boiler, remove the jacket
door and base access panel (Figure 32 , item 4,
page 62).
2. Inspect burners and all other components in the
boiler base.
3. If burners must be cleaned, raise rear of each burner
to release from support slot, slide forward and
remove. Then brush and vacuum the burners
thoroughly, making sure all ports are free of debris.
Carefully replace all burners, making sure burner
with pilot bracket is replaced in its original position
and all burners are upright (ports up).
4. Inspect the base insulation.
a. Pay attention to the WARNINGS on page 68
regarding working with insulation materials.
b. Verify that the insulation is intact and secure
against all four sides of the base.
If insulation is damaged or
displaced, do not operate the boiler.
Replace or reposition insulation as
necessary. Failure to replace
damaged insulation can result in a
fire hazard, causing severe personal
injury, death or substantial property
damage.

❏

Service . . . . . . . . . .
Oiled-bearing circulators
1. The circulator shipped with the CGa boiler is waterlubricated. No oiling is required.

2. Check other circulators in the system. Oil any
circulators requiring oil, following circulator
manufacturer’s instructions. Over-oiling will
damage the circulator.
Part Number 550-110-593/1099

Boiler Manual

❏

Start-up . . . . . . . . .
1. Perform start-up procedures section 6, pages 28-32,
including procedure to verify operation of burners
and vent damper on page 32.

4. Check gas piping, per manual sections 4 and 6,
verifying no indications of leakage and all piping
and connections are in good condition.

2. Verify cold fill pressure is correct and that fill system
is working properly.

5. Read the Lighting or Operating instructions
(manual section 8 or 9) applying to the boiler.

3. Verify antifreeze level (if used) is at the right
concentration and that inhibitor level is correct.

6. Start the boiler following the Lighting or Operating
instructions (manual section 8 or 9).

Check/test . . . . . . .
temperature. Boiler should cycle off. Return dial to
original setting.

Gas piping
1. Sniff near floor and around boiler area for any
indication of a gas leak.

2. Inspect and test additional limit controls or low
water cutoffs installed on system.

2. Test gas piping using bubble test, per section 4,
page 26 of this manual, if there is any indication of
a leak.

Figure 26 Automatic air vent, typical

Cold fill and operating pressures

1. While the system is cold, note the pressure reading
on the boiler pressure/temperature gauge. Verify that
cold fill pressure is correct.
2. Watch the pressure as the boiler and system heat
up to ensure pressure rise is normal. Too high a rise
would indicate a waterlogged or undersized
expansion tank.
59342

Air vents and air elimination

Expansion tank

1. Inspect automatic air vents (if used). Also inspect
air separators to ensure they are operational.

1. Expansion tanks provide space for water to move in
an out as the heating system water expands due to
temperature increase or contracts as the water cools.
Tanks may be open, closed or diaphragm or bladder
type. See section 3, page 16 of this manual for
suggested best location of expansion tanks and air
eliminators.
Open-type — located above highest radiator or
baseboard unit, usually in the attic or closet. Has a
gauge glass and overflow pipe to a drain.
Closed-type — welded gas tight and located above
boiler. Tank is partially filled with water, leaving an
air cushion for expansion.
• Make sure this type of tank is fitted with a tank
fitting, such as the B & G Tank-Trol or Taco
Taco-Trol. This fitting reduces gravity

2. The cap must be unscrewed one turn to allow air to
escape.
3. See Figure 26. If the air vent is leaking, remove cap
A and briefly push valve B and then release to clean
the valve seat.
4. Replace cap A by twisting all the way onto valve B
and then unscrewing one turn.

Limit controls and cutoffs
1. Inspect and test the boiler limit control. Verify
operation by turning control set point below boiler
Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

10b
❏

Service & maint. — annual start-up

continued

Check/test . . . . . . .
circulation of air-saturated tank water back to
the system and prevents the air from bubbling
up through the water as it returns from the
system.
•

Do not use automatic air vents in systems
with closed-type tanks. The air will escape

from the system instead of returning to the tank.
Eventually, the tank will waterlog and no longer
control pressurization. The boiler relief valve
will weep frequently.
Diaphragm- or bladder-type — welded gas tight

with a rubber membrane to separate the tank
pressurizing air and the water. May be located at
any point in the system, but most often found near
the boiler.
• Systems with this type of expansion tank
require at least one automatic air vent ,
preferably located on top of an air eliminator,
as shown in examples in manual section 3,
pages 16-25.
2. If relief valve has tended to weep frequently, the
expansion tank may be waterlogged or undersized.
Closed-type tank — tank is most likely
waterlogged. Install a tank fitting if not already
installed. Then check fill level per fitting
manufacturer’s instructions. If fill level is correct,
check tank size against manufacturer’s instructions.
Replace with a larger tank if necessary.
Diaphragm- or bladder-type — first, check tank

size to be sure it is large enough for the system. If
size is too small, add additional tank(s) as necessary
Figure 27

Relief valve, typical

59343

Part Number 550-110-593/1099

Boiler Manual

❏

Review with owner . . . . . . . .
1. Review the User’s Information Manual with the
owner.
2. Emphasize the need to perform the maintenance
schedule specified in the User’s Information
Manual (and in this manual as well).
3. Remind the owner of the need to call in a licensed

❏

Cleaning boiler heating surfaces
1. Shut down boiler:
• Follow “ To Turn Off Gas to Appliance ”
instructions on boiler and Lighting or
Operating instructions.
• Do not drain boiler unless it will be exposed to
freezing temperatures. If using antifreeze in
system, do not drain.
2. Follow shutdown procedure.
3. Remove venting system connection to boiler.
4. Remove top jacket panel. Turn back insulation.
5. Remove flue collector. Clean sealant from assembly
and sections.
6. Remove radiation plates hanging between sections.
7. Remove burners from base. Brush and vacuum
burners to remove all dust and lint. Verify that all
burner ports are free of debris.
8. Place newspapers in base of boiler to collect soot.
9. Clean between sections with wire flue brush.
10. Remove newspaper and soot. Vacuum or brush base

11a

contractor should the boiler or system exhibit any
unusual behavior.
4. Remind the owner to follow the proper shutdown
procedure and to schedule an annual start-up at the
beginning of the next heating season.

and surrounding area.
11. Reinstall radiation plates.
12. Replace collector box/transition assembly. Seal with
sealant. Obtain gas-tight seal to prevent flue gas
spillage and carbon monoxide emissions, resulting
in severe personal injury or death.
13. Replace insulation and jacket top panel.
14. Start up boiler following section 6, pages 28-32 of
this manual and the boiler Lighting or Operating
instructions. Excessive sooting indicates improper
gas combustion. If found, check for proper
combustion and make any necessary adjustments.
The boiler contains ceramic fiber
and fiberglass materials. Use care
when handling these materials per
instructions on page 68 of this
manual. Failure to comply could
result in severe personal injury.

Troubleshooting — procedure
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and
dangerous operation.
Never jumper (bypass) rollout thermal fuse element or
any other device except for momentary testing as
outlined in Troubleshooting Charts. Severe personal
injury, death or substantial property damage can result.
Burner access panel must be in position during boiler
operation to prevent momentary flame rollout on
ignition of main flame. Severe personal injury or
substantial property damage will result.
See pages 50 through 59 for additional troubleshooting
information.

Part Number 550-110-593/1099

Before troubleshooting:
1. Have the following items:
a. Voltmeter that can check 120 VAC and 24
VAC.
b. Microammeter with a minimum scale range
of 0-25.
c. Continuity checker.
d. U-tube manometer.
2. Check for 120 VAC (minimum 102 VAC to
maximum 132 VAC) to boiler.
3. Make sure thermostat is calling for heat and contacts
(including appropriate zone controls) are closed.
Check for 24 VAC between thermostat wire nuts and
ground.
49

GOLD CGa Gas-Fired Water Boiler

Part Number 550-110-593/1099

Boiler Manual

11b

Troubleshooting — standing pilot boilers

Chart 1 — Standing pilot — Boiler will not fire
Is damper harness securely plugged in at both ends?
Secure connections.

Check for loose wire connections or bad relay on
transformer.

Yes

Is 24VAC present across transformer terminals C & Y?
No

Check for open thermostat, LWCO, high limit, spill switch or
rollout thermal fuse element contacts or check for loose
wire connections.
If LWCO, spill switch or rollout thermal fuse
element contacts are open, determine cause
and correct condition. Failure to do so will
cause severe personal injury, death or
substantial property damage.

Yes

Is 24VAC present across transformer terminal C and yellow
wire on vent damper connector?
No

Yes

Is vent damper rotated open?
Yes

No
Check/repair out of round stack section. Does vent damper
rotate open?
No

Is 24VAC present across gas valve terminals?
No

Yes

Replace actuator.
Retest.

Is main flame on now?
No

Open thermostat contacts for 30 seconds. Vent damper will
rotate to closed position. Close thermostat contacts. Vent
damper will rotate to open position. Is 24VAC present
across gas valve terminals?
Yes

Check continuity of each wire in damper harness. Does
continuity exist for each wire? See Table below.
Yes

Replace damper
wiring harness.
Retest.

Remove damper harness from
damper harness plug.
TEMPORARILY install jumper
between terminal 2 and
terminal 5 on damper plug in
boiler wiring harness. See
figure, right. Does boiler fire?
No

Replace gas valve.
Retest.

Part Number 550-110-593/1099

Yes

Replace damper
actuator. Retest.

Yes
Retest

Is gas valve cock turned to ON position?
No

Yes

Turn gas valve cock to
ON position. Retest.

Replace gas valve.
Retest

Damper harness
Continuity Table
6 Pin Molex
Pin Number

4 Pin Molex
Pin Number

1
2
3
4
5
6

1
3
4
N/C
2
N/C

Pin side of connectors

59341

GOLD CGa Gas-Fired Water Boiler

11c

Troubleshooting — spark-ignited pilot boilers
The information on this page and pages 53 through 59
apply only to spark-ignited pilot CGa boilers. These
boilers are equipped with an ignition control module
that has indicator lights to show control status. Charts 2
through 7, pages 54-59, help you identify problems
based on indicator light conditions.
Make sure ground wiring is installed per wiring
diagram. Good grounding is extremely important for
proper operation.
Solder or water splatter between plugs and circuit
board can cause improper operation of control module.
Place a shield over the boiler internal controls and
components during installation. Failure to comply could
result in severe personal injury, death or substantial
property damage.

Figure 29 CGa Ignition control module

Control indicator lights —
lockout modes
See Charts 2 through 7, pages 54-59 in this section, for
detailed troubleshooting procedures.
To reset control after a lockout, turn off power at the
120 VAC service switch or turn down all thermostats.
Wait 45 seconds. Then restore power or call for heat.
POWER light flashing alone
Usually indicates reversed polarity of 120 VAC power
wires.
POWER and TSTAT CIRC lights flashing
Usually indicates stray voltage on external thermostat
circuit wires (usually due to miswired 3-wire zone valve).
POWER and DAMPER lights flashing
Usually indicates vent damper failed to open within
5 minutes.
POWER and FLAME lights flashing
Usually indicates false flame sense or flame sensed when
it shouldn’t be there.

Control indicator lights —
non-lockout modes
FLAME light flashing alone
Usually indicates pilot flame was not established within
15 seconds from application of spark. Control will flash
light, but will continue to cycle indefinitely until flame
is established or problem is corrected.
DAMPER light flashing alone
Usually indicates damper opened during run cycle.
Boiler will not lockout, but won’t heat unless problem
is corrected.

Troubleshooting the control
module
59346

See Figure 30, page 53, for location of harness plug
receptacles and plugs on the control module.
Part Number 550-110-593/1099

Boiler Manual

Figure 30

Control module connections
Black
120 VAC H

High voltage to
pilot spark electrode

Black

120 VAC H

White

SJO cable
to J-box

120 VAC N
120 VAC to
transformer

Entrance
ground

Green

Chassis
ground

Green
White

120 VAC N

Red wire to
gas valve MV

120 VAC IN
Black wires to
thermostat circuit

Yellow wires to limit control
and rollout switch

Brown

Red

White wire to
gas valve MV/PV

Blue wire to
gas valve PV

24 VAC
24 VAC from transformer

Indicator lights

24 VAC control
circuits

FLAME

(Constant)

DAMPER
LIMIT
TSTAT CIRC

24 VAC Common

4 1

Green

24 VAC call for heat

5 2

Green

6 3

Connector plug
in vent damper

24 VAC
Black

From end switch
Red

Jumpered to pin "4"
Green

POWER
24 VAC to
vent damper

High voltage to spark electrode
120 VAC to transformer
Yellow

120 VAC IN
120 VAC H

White
24 VAC control circuits

24 VAC from transformer

120 VAC N

120 VAC to circulator

24 VAC vent damper connections
120 VAC to circulator

59345

Part Number 550-110-593/1099

Sense wire to flame sensor

Flame sense wire to pilot

GOLD CGa Gas-Fired Water Boiler

11c

Troubleshooting — spark-ignited pilot boilers

Chart 2 — Spark-ignited pilot — Troubleshooting POWER light status
— Usually indicates reversed 120 VAC polarity if POWER light flashes by itself —
Electrical shock hazard — Wherever you see ▲TURN OFF POWER▲, follow the instructions. Failure to follow
instructions could result in severe personal injury, death or substantial property damage.

Is POWER light off?
No

•
Yes

•
•

Is POWER light...
Flashing
alone

TSTAT CIRC
light flashing

Chart
3

DAMPER
light flashing

Chart
4

FLAME
light flashing

Chart
5

Does voltmeter indicate 120 VAC?

On steady
(not flashing)

Flashing with
another light

Make sure service switch or circuit breaker is on or
fuses are good.
Remove 120 VAC IN plug (Figure 30, Item 3, page
53) on control module.
Using voltmeter, check across top and bottom pins
of 120 VAC IN plug.

Yes

Problem is with incoming
electricity. Have licensed
electrician repair circuit.
Chart
6

For insufficient heat or no heat problem, go to
Chart 7 if POWER light is on steady, with no other
light flashing.

•
•
•

Reconnect 120 VAC IN plug.
Remove 120 VAC transformer PRIMARY plug
(Figure 30, Item 2, page 53) on control module.
Using voltmeter, check across top and bottom pins
of PRIMARY receptacle.

Does voltmeter indicate 120 VAC?
No
•
•

•

Usually indicates polarity on incoming 120 VAC power
line is wrong.
▲TURN OFF POWER▲ at service switch or breaker,
then reverse the HOT and NEUTRAL wires entering
the boiler in the J-box.
Restore POWER at service switch or breaker.

Replace control module.
Retest.

•
•

Is POWER light flashing now?
No

Yes

•

Reinstall 120 VAC transformer PRIMARY plug.
Remove 24 VAC transformer plug (Figure 30, Item 5,
page 53) on control module.
Using voltmeter, check across pins of receptacle.

Does voltmeter indicate 120 VAC?
No

Boiler should now
operate normally.

Have system checked by a
licensed electricain.
If problem persists, call your
local Weil-McLain sales
representative.

Replace transformer.
Retest.

Yes

Replace control module.
Retest.

Part Number 550-110-593/1099

Boiler Manual

continued
Chart 3 — Spark-ignited pilot — TSTAT CIRC & POWER lights flashing
— Usually indicates 48 VAC on thermostat circuit (stray voltage) —

Electrical shock hazard — Wherever you see ▲TURN OFF POWER▲, follow the instructions. Failure to follow
instructions could result in severe personal injury, death or substantial property damage.

• Disconnect the two external wires connected to the boiler
thermostat leads (two black low voltage leads in J-box).
• Connect a voltmeter across these two incoming wires.
Close each thermostat, zone valve and relay in the
external circuit one at a time and check the voltmeter
reading across the wires.
• There should NEVER be a voltage reading.

• If a voltage does occur under any condition, check and
correct the external wiring. (This is a common problem
when using 3-wire zone valves.)
• Once the external thermostat circuit wiring is checked and
corrected if necessary, reconnect the external thermostat
circuit wires to the boiler thermostat wires and allow the
boiler to cycle.

Did you find a voltage across the two external thermostat circuit wires?
Yes

• Leave external boiler thermostat connection wires
disconnected from boiler.

• If no voltage is found under any condition of the external
thermostat circuit, connect the two boiler thermostat
connection leads together (or jumper the boiler aquastat
T-T terminals).

• Troubleshoot the external thermostat circuit until you find
the source of the stray voltage. (Pay close attention to
the wiring connections to 3-wire zone valves.)

• Turn off power to the boiler for 1 minute.

• Correct the problem and repeat the voltmeter test above,
verifying there is no longer a voltage reading under any
condition in the external thermostat circuit.

• Turn on power and allow boiler to cycle.

Do the TSTAT and POWER lights still flash?
No

• Boiler should now operate per the normal sequence of
operation shown in Figure 24, page 37.

Part Number 550-110-593/1099

Yes

• Replace control module.
• Retest.

GOLD CGa Gas-Fired Water Boiler

11c

Troubleshooting — spark-ignited pilot boilers

Chart 4 — Spark-ignited pilot — DAMPER light flashing
— If POWER light is flashing: Usually indicates vent damper failed to prove open within 5 minutes —
— If POWER light is steady: Usually indicates vent damper closed during run cycle —
Electrical shock hazard — Wherever you see ▲TURN OFF POWER▲, follow the instructions. Failure to follow
instructions could result in severe personal injury, death or substantial property damage.
• Reset boiler control by turning off power at service switch or turning down thermostat for at least 45 seconds.
• Thermostat should call for heat and appropriate zone valves open. The TSTAT CIRC and LIMIT lights should come on.

Does vent damper operate?
No

Yes

• Wait 45 seconds.

Does vent damper operate?
No

Yes

• Remove DAMPER plug (Figure 30, Item 6, page 53)
from plug receptacle of control module.
• Place voltmeter leads across the top two pins (1 and 4)
of the DAMPER receptacle.

• Wait 5 minutes.

Is DAMPER light flashing?
No

Yes

Does the voltmeter indicate 24 VAC?
No

Yes

• Try reseating plug in
module receptacle and
restart.
• If vent damper still does
not work, replace vent
damper assembly or
actuator.
• Retest.

• Boiler should be in
normal operating
sequence.
• Observe operation until
thermostat is satisfied.

Does vent damper actuator
indicator show damper is
open?

Yes

Are the TSTAT CIRC and LIMIT lights on steady?
Yes

• Replace control
module.
• Retest.

• Make sure thermostat is
calling for heat. If lights
still don't come on, see
Chart 7.

• Replace vent damper
assembly or actuator.
• Retest.

• Remove damper wiring
plug at damper and firmly
reconnect.
• Recheck boiler operation.
• If problem persists,
replace vent damper
assembly or actuator.

Part Number 550-110-593/1099

Boiler Manual

continued
Chart 5 — Spark-ignited pilot — FLAME & POWER lights flashing
— Usually indicates flame sensed when it shouldn't be there —

Are manual main shutoff valve and gas valve open?
No

•
•
•
•
•

Yes

Leave main manual gas valve closed.
Turn off power to boiler at service switch or breaker.
Wait at least 45 seconds.
Turn on power to boiler.
Restart boiler, following Operating instructions in this
manual or on boiler label.

•
•
•
•

Turn off power to the boiler at service switch or breaker.
Wait at least 45 seconds.
Turn on power to boiler.
Restart boiler, following Operating instructions in this
manual or on boiler label.
• Look through the pilot inspection port to see if the pilot is
burning.

Do FLAME and POWER lights still flash?
No

Is pilot burning?

Yes
No

Yes

• Replace control module.
• Retest.

• Allow boiler to continue cycling.

Are FLAME and POWER lights flashing?

• ▲TURN OFF POWER▲
to boiler at service switch
or breaker.
• Open main manual gas
valve.
• Turn on power to boiler
at service switch or
breaker.
• Restart boiler per
operating instructions.
• Perform start-up
procedures in boiler
manual to verify proper
operation.

Part Number 550-110-593/1099

• Boiler may now be
operating
normally.
• Perform start-up
procedures in
boiler manual to
verify proper
operation.

Yes

• Replace gas valve.
• Retest boiler.

Are FLAME and POWER lights flashing?
No

Yes

• Replace control
module.

• Boiler should now
operate normally.

• Replace control
module.

• Retest.

• Original flashing
FLAME light
caused by gas
valve not
operating
properly.

• Retest.

• See normal
sequence of
operation,
Figure 24,
page 37.

GOLD CGa Gas-Fired Water Boiler

11c

Troubleshooting — spark-ignited pilot boilers

Chart 6 — Spark-ignited pilot — FLAME light flashing and POWER light on steady
ALSO — Troubleshooting failure to establish main flame
Electrical shock hazard — Wherever you see ▲TURN OFF POWER▲, follow the instructions. Failure to follow
instructions could result in severe personal injury, death or substantial property damage.
• Are main manual shutoff valve and boiler gas valve open?
No

Yes

• ▲TURN OFF POWER▲ to boiler at service switch or breaker.
• Open main manual shutoff valve and boiler gas valve (per
Operating instructions in this manual). Wait at least 45
seconds.
• Turn on power at service switch or breaker. Allow boiler to
cycle.
Does FLAME light flash now?
No
Yes

• Boiler should be in
normal operating
sequence.
• Observe operation
until thermostat is
satisfied and blower
has completed its
post-purge cycle.

• Verify inlet gas pressure at gas
valve:
Natural gas — 5.0" w.c. min/14.0"
w.c. max
Propane — 11.0" w.c. min/14.0"
w.c. max

Is gas present at gas valve inlet and
within above range?
Yes
No

• Is pilot flame visible through inspection port?
No

Yes

• Check the voltage across
main gas valve terminals of
the gas valve.

• Make sure ground wire
terminal is securely fastened
to control module mounting
screw.

Is 24 VAC present there?
Yes
No

• If the wiring from the
control module to gas
valve is intact, replace the
control module.
• Retest.

• Check the voltage across
main gas valve terminals of
the gas valve.

Is 24 VAC present there?
No
Yes

• Verify inlet gas pressure at gas valve:
Natural gas — 5.0" w.c. min/14.0" w.c. max

• ▲TURN OFF POWER▲ to
boiler at service switch or
breaker.
• Remove base access panel
(see Figure 32, page 62 for
location).
•

•

Verify pilot gas line is not
kinked, obstructed or damaged
and is correctly attached to
pilot and gas valve.
Verify pilot ignition electrode,
electrode ceramic and spark
lead wire from control are in
good condition. Spark gap
should be approximately 1/8".
Correct any above problems,
replacing pilot if burner or
wiring is damaged.
Reinstall base access panel to
operate boiler for retest after
any changes or corrections.
If none of the above corrects
problem, then replace the
control module, reinstall base
access panel, and retest.

Propane — 11.0" w.c. min/14.0" w.c. max

Is gas present at gas valve inlet and within above range?
• Contact gas supplier to correct
pressure or gas supply.

• ▲TURN OFF POWER▲ to boiler
at service switch or breaker.
• Remove base access panel (see
Figure 32, page 62 for location).

•

Verify pilot burner is securely
attached to pilot bracket, bracket is
securely attached to cross tie, and
there is no corrosion on the parts
which would affect the ground path
for flame sense.
Verify that pilot flame rod, flame rod
ceramic and lead wire from control
module to flame rod are in good
condition.
Correct any above problems,
replacing pilot if burner or wiring is
damaged.

Yes

• ▲TURN OFF POWER▲ to boiler at service switch or breaker.
• Check flame signal — Detach sense lead from igntion control
(Figure 30, item 8, page 53).
• Connect negative lead of MICROAMMETER to control sense
terminal (Figure 30, item 8, page 53). Connect positive lead of
MICROAMMETER to sense wire.
• DISCONNECT red wire connected to man gas valve terminal of
the gas valve.
• Turn on power to boiler and allow to cycle. As soon as pilot is
burning, the MICROAMMETER should read at least 1.0
microamp.

Is flame signal at least 1.0 microamp?
No
Yes
• If none of the previous steps
(including replacing pilot)
corrects problem, then replace
the control module, reinstall
base access panel and retest.

• If the wiring from the
control module to gas
valve is intact, replace the
control module and retest.

Part Number 550-110-593/1099

Boiler Manual

continued
Chart 7 — Spark-ignited pilot — Insufficient heat or no heat (POWER light on steady)
Electrical shock hazard — Wherever you see ▲TURN OFF POWER▲, follow the instructions. Failure to follow
instructions could result in severe personal injury, death or substantial property damage.
• Has it been at least 5 minutes since setting thermostat to
call for heat? If not, wait 5 minutes. Is system heating?
• Is thermostat set to call for heat? Remove thermostat
wires at boiler and check continuity across the two wires.
If circuit isn't closed, check external thermostat (zone
valve, relay, etc.) wiring. Correct problems and retry.
• Reconnect external thermostat wiring at boiler.

Is thermostat circuit closed (continuity across wires)?
No

Is boiler System circulator operating?
No

• Remove CIRCULATOR harness plug from
CIRCULATOR plug receptacle (Figure 30, Item
7, page 53). Check with voltmeter across pins of
control module receptacle.
Does voltmeter show 120 VAC across pins?

Yes

Are all red lights off?
No

Yes

Wait 30 seconds.
Are all red lights off?
No

• Boiler is in standby.
• Set thermostat to call for
heat and recheck
operation.
• Verify Sequence of
operation, Figure 24,
page 37.

Yes

• Replace control
module.
• Retest.

• Repair/replace
circulator. Retest.
• Repair/replace
wiring. Retest.

• Wait 5 minutes.

Yes

Is FLAME light on?
Yes

Replace control
module. Retest.
• If you have sufficient heat — boiler should be in normal
operating sequence. (See normal sequence of
operation, Figure 24, page 37.)
• If you have less than sufficient heat —

Is vent or combustion air piping free of blockage?
No
Yes
• Correct conditions and
recheck operation.
• See Figure 24, page 37
for normal sequence of
operation.

Contact your Weil-McLain
sales representative.

• Wait for boiler water to cool to temperature 20 to 30 ˚F
lower than temperature set on limit switch.
No

Are limit switch contacts closed?
Yes

• Replace
limit switch.
• Retest.

• Boiler water temperature exceeded
setting on limit switch with thermostat
calling for heat. Boiler is OK. (See normal
sequence of operation, Figure 24, p. 37.)
• Also check setting on limit switch (should
be above 140˚F.).

Part Number 550-110-593/1099

Is LIMIT light on?
No

Yes

• Check limit switch
contacts with continuity
checker.

Are limit switch contacts
closed?
No

Yes

• Replace control module.
• Retest.

Check spill switch and
rollout switch continuity —
are switches closed?
No

Yes

• Reset spill switch, or replace
rollout switch.
If rollout thermal fuse element or
spill switch has opened, determine
cause and correct condition.
Failure to do so will cause severe
personal injury, death or
substantial property damage.

• Check any other
limit controls wired
into the limit
circuit. If all are
OK, then replace
control module.
• Retest.

GOLD CGa Gas-Fired Water Boiler

12a

Replacement parts

Section assembly ............................................... 61

Base assembly .................................................... 62

Jacket assembly ................................................. 63

Trim assembly .................................................... 64

Gas control assembly — standing pilot .............. 65

Gas control assembly — spark-ignited pilot ....... 65

Replacement parts must be purchased through a local Weil-McLain
distributor. When ordering, specify boiler model and size and include
description and part number of replacement part. Results from using
modified or other manufactured parts will not be covered by warranty and
may damage boiler or impair operation.

Weil-McLain part numbers are found in Weil-McLain Boilers and Controls
Repair Parts Lists.

The boiler contains ceramic fiber and fiberglass materials. Use care when
handling these materials per instructions on page 68 of this manual. Failure
to comply could result in severe personal injury.
60

Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler

13a

Dimensions

Figure 36 Dimensional drawing — ALL DIMENSIONS IN INCHES
6¹⁄₄
T OP VIEW
Note 1: Boiler supply and return tappings are both 1¼" NPT.
See Table 3, page 16 for recommended system supply and return piping sizes.
Note 2: Boiler circulator is shipped loose. Circulator may be
mounted on either boiler supply or return piping.
Circulator flange provided with boiler is same size as
recommended pipe size in Table 3, page 16.

2³⁄₈
13¹⁄₄

4³⁄₄

MODEL

CGi

NOTE 2

28³⁄₈

NOTE 2

19
13¹¹₁₆

23¹⁄₄
L EFT SIDE

1⁵⁄₈

W
F RONT

R IGHT SIDE

Part Number 550-110-593/1099

Boiler Manual

13b
Boiler
model
number

Ratings

Input
(Btuh)

DOE
Heating
capacity
(Btuh)

(Note 1)

DOE

0–2,000 feet
altitude
Input
(Btuh)

Output
(Btuh)

2,000–4,500 feet
altitude
Input
(Btuh)

Output
(Btuh)

(Note 2)

Net
Boiler
I=B=R
water
ratings content
(Btuh) (gallons)

DOE
Seasonal efficiency
(% A.F.U.E)
SPDN

SPDL

PIDN

Chimney
and
breeching
size

(Note 3)

CGa-25

52,000

44,000

52,000

44,000

46,800

39,000

38,000

1.5

81.5

83.3

84.0

4"I.D. x 20’

CGa-3

70,000

59,000

70,000

59,000

63,000

53,000

51,000

1.5

81.6

83.7

84.0

4"I.D. x 20’

CGa-4

105,000

88,000 105,000

88,000

94,500

79,000

77,000

2.1

81.7

83.7

84.0

5"I.D. x 20’

CGa-5

140,000

117,000 140,000 117,000 126,000 105,000 102,000

2.7

81.8

83.7

83.5

6"I.D. x 20’

CGa-6

175,000

146,000 175,000 146,000 157,500 131,000 127,000

3.3

81.9

83.6

83.2

6"I.D. x 20’

CGa-7

210,000

175,000 210,000 175,000 189,000 157,000 152,000

3.8

82.0

83.6

83.0

7"I.D. x 20’

CGa-8

245,000

204,000 245,000 204,000 220,500 183,000 177,000

4.4

82.1

83.6

82.7

7"I.D. x 20’

Notes

1. See Table 7 for available pilot systems. The suffix shown
in the table is added to the boiler model number. (Not
available for millivolt systems.)
2. Based on standard test procedures prescribed by the
United States Department of Energy.
3. Net I=B=R ratings are based on net installed radiation of
sufficient quantity for the requirements of the building
and nothing need be added for normal piping and pickup.
Ratings are based on a piping and pickup allowance of
1.15. An additional allowance should be made for unusual
piping and pickup loads.

Table 7

Ignition system model suffixes

Pilot ignition system

Natural gas

Propane gas

Standing pilot

SPDN

SPDL

Spark-ignited pilot

PIDN

Not available

Install CGa boilers for residential radiant panel systems, converted gravity heating systems or other low water
temperature applications per instructions in this manual to avoid damage due to condensation.
CGa boilers are CSA design certified for installation on combustible flooring.
CGa boilers are ASME rated for 50 psig working pressure.
Part Number 550-110-593/1099

GOLD CGa Gas-Fired Water Boiler — Boiler Manual

Part Number 550-110-593/1099

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