Boiler Manual
Series 3
Gas-Fired Water Boilers
• Maintenance
• Parts
• Installation
• Startup
Part Number 550-142-300/0520
Now With Built In
Low Water Cut Off Functionality
This manual must only be used by a qualified heating installer/service technician. Before installing, read all
instructions, including this manual, and any related supplements. Perform steps in the order given. Failure to comply
could result in severe personal injury, death or substantial property damage.
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
a supply to system
b return from system
c flue outlet
d burner manifold
e gas valve
f pressure/temperature gauge
g relief valve
h air vent connection
i flame rollout switch
j burner orifice
k pilot burner, typical
l stainless steel burners
m cast iron boiler sections
n flue collector
o junction box
Other boiler components:
①
Control module
The control module 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.
For natural gas, 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.
For propane gas, 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, wait 1 minute, then start a new
cycle. If flame is still not sensed after the second trial, two more attempts are made with 5 minute and 60 minute
wait periods in between. If flame is not sensed after 4 tries, control will lockout and flash all lights. Control must
be manually reset to place back into service. 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 49
for details.
②
Transformer
The control transformer reduces line voltage to 24 volts for the gas valve and limit circuit.
③
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.
④
Spill switch
The spill switch will shut down the boiler (requiring manual reset of the switch reset button) if the vent system
becomes blocked.
⑤
Water temperature/ LWCO sensor
The water temperature/LWCO sensor provides a signal to the control module to turn off the gas valve if the tem-
perature in the boiler goes above its setting or if a low water condition is sensed. (The circulator will continue to
run as long as there is a call for heat.)
⑥
Boiler circulator
The boiler circulator circulates water through the external (system) piping. The circulator is shipped loose, and
can be mounted on either the boiler supply or return piping. The factory-installed circulator wiring harness
provides ample length for either location. NOTE — The control module provides a pump exercising routine. If
the boiler is not operated for 30 days, the control module will power the circulator for 30 seconds, then turn off.
⑦
Vent damper
The vent damper closes during off cycles to reduce heat loss from the house up the vent.
How it works . . .
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
CGa Series 3 Gas-Fired Water Boiler
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
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.
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 accumula-
tion 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.
Contents
How it works .................................................... 2-3
Hazard definitions ............................................... 4
Please read before proceeding ............................ 5
1 Prepare boiler location ...................................6–11
2 Prepare boiler ............................................... 12-15
3 Water piping ................................................. 16-25
4 Gas piping ......................................................... 26
5 Field wiring ....................................................... 27
6 Start-up ........................................................ 28-32
7 Check-out procedure ......................................... 33
8 Department of Energy Compliance ................... 34
9 Operation – spark-ignited pilot boilers .......... 34-41
10 Service and maintenance ............................. 42-47
11 Troubleshooting:
Spark-ignited pilot boilers ............................ 48-56
12 Replacement parts ....................................... 58-63
13 Dimensions and ratings ................................ 64-65
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Failure to adhere to the guidelines below can result in severe personal injury, death or substantial property damage.
When servicing boiler —
• To avoid electric shock, disconnect all
electrical supplies to the boiler before
performing maintenance.
• To avoid severe burns, allow boiler to
cool before performing maintenance.
• This boiler contains ceramic fiber
and fiberglass materials. Refer to
the WARNING and instructions on
page 66.
Boiler operation —
• Do not block flow of combustion or
ventilation air to boiler.
• Should overheating occur or gas sup-
ply fail to shut off, do not turn off or
disconnect electrical supply to pump.
Instead, shut off the gas supply at a
location external to the appliance.
Combustion air —
• DO NOT install combustion air in-
take where there is a risk of combus-
tion air contamination.
Boiler water —
• Do not use petroleum-based cleaning
or sealing compounds in boiler sys-
tem. Gaskets and seals in the system
may be damaged. This can result in
substantial property damage.
• Do not use “homemade cures” or
“boiler patent medicines”. Serious
damage to boiler, personnel and/or
property may result.
• Continual fresh makeup water will
reduce boiler life. Mineral buildup in
sections reduces heat transfer, over-
heats 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 a hot boiler.
Thermal shock can cause heat ex-
changer to crack.
Freeze protection fluids —
• NEVER use automotive or standard
glycol antifreeze. Use only freeze-
protection fluids made for hydronic
systems. Follow all guidelines given
by the antifreeze manufacturer.
Thoroughly clean and flush any re-
placement boiler system that has used
glycol before installing the new boiler
Frozen Water Damage
Hazard
Residences or buildings that are unat-
tended in severely cold weather, boiler
system components failures, power out-
ages, or other electrical system failures
could result in frozen plumbing and water
damage in a matter of hours. For your
protection, take preventative actions such
as having a security system installed that
operates during power outages, senses low
temperature, and initiates an effective ac-
tion. Consult with your boiler contractor
or a home security agency.
If any part of a boiler, burner or its controls has
been sprayed with or submerged under water,
either partially or fully, DO NOT attempt to op-
erate the boiler until the boiler has been either
replaced or completely repaired, inspected, and
you are sure that the boiler and all components
are in good condition and fully reliable.
Otherwise, by operating this boiler, you will cause
a fire or explosion hazard, and an electrical shock
hazard, leading to serious injury, death, or substan-
tial property damage. See the instructions at right.
Saltwater Damage — The exposure of boiler components to
saltwater can have both immediate and long-term effects. While the
immediate effects of saltwater damage are similar to those of fresh-
water (shorting out of electrical components, washing out of critical
lubricants, etc.), the salt and other contaminants left behind can lead
to longer term issues after the water is gone due to the conductive
and corrosive nature of the salt residue. Therefore, Weil-McLain
equipment contaminated with saltwater or polluted water will no
longer be covered under warranty and should be replaced.
Electrical Damage — If any electrical component or wiring
came into contact with water, or was suspected to have come into
contact with water, replace the boiler with a new Weil-McLain boiler.
Installer— Read all instructions, including this
manual and all other information shipped with the
boiler, before installing. Perform steps in the order
give no prevent personal injury or death.
User — This manual is for use only by a qualified
heating installer/service technician. Refer to User’s
Information Manual for your reference.
User — Have this boiler serviced/inspected by a
qualified service technician, at least annually.
Failure to comply with the above could result in severe
personal injury, death or substantial property damage.
Write in the Consumer Protection (CP) number in
the space provided on the Installation certificate on
page 33 if not already shown.
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.
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.
Please read before proceeding
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Installations must follow these codes:
• Local, state, provincial, and national codes, laws, regulations and ordinances.
• National Fuel Gas Code, ANSI Z223.1/NFPA 54 – latest edition.
• Where required by the authority having jurisdiction, the installation must conform
to the Standard for Controls and Safety Devices for Automatically Fired Boilers,
ANSI/ASME CSD-1 –– latest edition.
• National Electrical Code, ANSI /NFPA 70 – latest edition.
• For Canada only: Natural Gas and Propane Installation Code, CAN/CSA B149.1
or B149.2 Installation Code, CSA C22.1 Canadian Electrical Code Part 1 and any
local codes.
The CGa boiler gas manifold and controls meet safe operating and
other performance criteria when boiler underwent tests specified
in ANSI Z21.13 – latest edition.
Before locating the boiler,
check the following:
• Check for nearby connection to:
• System water piping
• Venting connections
• Gas supply piping
• Electrical power
• Check area around boiler. Remove any combustible materials, gasoline
and other flammable liquids, or other contaminants.
Failure to keep boiler area clear and free of combustible materials,
gasoline and other flammable liquids and vapors
can result in
severe personal injury, death or substantial property damage.
•
Boiler must be installed so that gas control system components are protected from
dripping or spraying water or rain during operation or service.
• If new boiler will replace existing boiler, check for and correct system problems,
such as:
1. System leaks causing oxygen corrosion or section cracks from hard water
deposits.
2. Incorrectly-sized expansion tank.
3. Lack of antifreeze in boiler water causing system and boiler to freeze and
leak.
Prepare boiler location — codes & checklist
1a
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Recommended SERVICE clearances
(Fig. 1a)
1. Provide clearances for cleaning and servicing the boiler and for
access to controls and components. See Figure 1a for recommen-
dations.
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.
Required MINIMUM clearances (Fig. 1b)
Never install the boiler in a space with clear-
ances less than the minimum clearances shown
in Figure 1b
. Failure to comply can result in severe
personal injury, death or substantial property dam-
age and reduced boiler life.
1.
Hot water pipes: at least ¹⁄₂ inch from combustible material.
2.
Single-wall vent pipe: at least 6 inches from combustible mate-
rial.
3.
Type B double-wall metal vent pipe: refer to vent manufacturer’s
recommendation for clearances to combustible material.
If any clearance is less than in Figure 1a, pro-
vide openings for combustion and ventilation
air located on the wall or door opposite the
boiler FRONT (see Figure 1b)
.
These openings must be located as shown in Figure 1b to provide
proper air flow around the boiler. The free area of each opening
(after deducting for louvers) must be at least one square inch
per 1,000 Btuh
of boiler input. If the building is of unusually
tight construction (see page 11 for definition), the air openings
must connect directly to outside or the building must have air
openings to the outside as specified on page 11.
If clearances are equal to or greater than Figure 1a, see pages 10
and 11 for location and sizing of combustion air openings.
Failure to comply can result in severe personal injury, death or
substantial property damage and reduced boiler life.
Flooring
The CGa boiler is approved for installation on combustible
flooring, but must never be installed on carpeting.
Do not install boiler on carpeting even
if foundation is used. Fire can result,
causing severe personal injury, death
or substantial property damage.
Foundation
1. Provide a solid brick or minimum 2-inch thick concrete
foundation pad if any of the following is true:
• floor can become flooded.
• the boiler mounting area is not level.
2. Minimum dimensions are 25” length by:
Residential garage installations
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, – latest edition:
• 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.
Minimum foundation width:
CGa-25/3 12” CGa-6 21”
CGa-4 15” CGa-7 24”
CGa-5 18” CGa-8 27”
Figure 1b Required MINIMUM clearances
Figure 1a
Recommended
service
clearances
(see WARNING
below)
1b
Prepare boiler location — clearances
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Prepare boiler location — vent system
1c
Failure to follow all instructions can result in flue gas spillage and carbon monoxide emissions, causing severe
personal injury or death.
When removing boiler from an
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 op-
eration, 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 con-
nected to the common venting system are located
and other spaces of the building. Turn on clothes
dryers and any appliance not connected to the com-
mon 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 sum-
mer exhaust fan. Close fireplace dampers.
d.
Place in operation the appliance being inspected.
Follow the 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 previ-
ous 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/NFPA 54
-latest edition. Correct by resizing to approach the mini-
mum size as determined using the appropriate tables in
Part 13 of that code. Canadian installations must comply
with Natural Gas and Propane Installation Code, CAN/
CSA B149.1 or B149.2 Installation Code.
Chimney or vent require-
ments
1. Venting must be installed according to Part 7, Vent-
ing 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 65 for minimum chimney
or vent sizes. A chimney or vent
without a listed
cap
should extend at least 3 feet above the highest
point
where it passes through a roof of a building
and at least 2 feet higher than any portion of a
building within a horizontal distance of 10 feet
.
A chimney or vent must not extend less than the
distances stated above.
3. A lined chimney is preferred and must be used when
required by local, state, provincial and national
codes, laws, regulations and ordinances. Vitreous tile
linings with joints that prevent retention of moisture
and linings made of noncorrosive materials are best.
Advice for flue connections and chimney linings can
be obtained from local gas utility.
Type B double-
wall metal vent pipe or single-wall vent pipe may
be used as a liner.
4. Cold masonry chimneys, also known as outside
chimneys, typically have one or more walls ex-
posed to outside air. When any atmospheric gas-
fired boiler with automatic vent damper is vented
through this type of chimney, the potential exists for
condensation to occur. Condensation can damage
a masonry chimney. Weil-McLain recommends the
following to prevent possible damage.
a. Line chimney with corrosion-resistant metal
liner such as AL29-4C® single-wall stainless
steel or B-vent. Size liner per National Fuel
Gas Code ANSI Z223.1 - latest edition.
b. Provide drain trap to remove any condensate.
5. Where two or more gas appliances vent into a
common chimney or vent, equivalent area should
be
at least equal to area of vent outlet on largest
appliance plus 50 percent of vent outlet area on
additional appliance.
Do not alter boiler draft hood or place any obstruction or non-approved vent damper in breeching or vent system.
CSA certification will become void. Flue gas spillage and carbon monoxide emissions will occur causing severe
personal injury or death.
Inspect existing chimney before installing boiler. Failure to clean or replace perforated pipe or tile lining will cause
severe personal injury or death.
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Prepare boiler location — air contamination
Table 1 Corrosive contaminants and likely locations
1d
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.
Products to avoid
Spray cans containing chloro/uorocarbons
Permanent wave solutions
Chlorinated waxes/cleaners
Chlorine-based swimming pool chemicals
Calcium chloride used for thawing
Sodium chloride used for water softening
Refrigerant leaks
Paint or varnish removers
Hydrochloric acid/muriatic acid
Cements and glues
Antistatic fabric softeners used in clothes dryers
Chlorine-type bleaches, detergents, and cleaning
solvents found in household laundry rooms
Adhesives used to fasten building products and other
similar products
Airborne particulates (drywall dust, berglass particles,
road or gravel dust, lint, etc.)
Areas likely to have contaminants
Dry cleaning/laundry areas and establishments
Swimming pools
Metal fabrication plants
Beauty shops
Refrigeration repair shops
Photo processing plants
Auto body shops
Plastic manufacturing plants
Furniture renishing areas and establishments
New building construction
Remodeling areas
Garages with workshops
Buildings under construction (where air is contaminated
with particulates)
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Figure 5 Air from outdoors — horizontal ducts
Figure 4 Air from outdoors — vertical ducts
Figure 2 Air openings to interior spaces
Figure 3 Air directly through outside wall
Air opening options
Two openings — Air supply from inside the building
✷
1. If the building is of unusually tight construction (see definition, next
page), the building must also be provided with air openings directly
to the outside
, sized and located per Figure 3, Figure 4 or Figure 5.
2. Buildings of typical construction should provide adequate combustion
air from natural infiltration, so additional air openings to the building
are not required.
3. See Figure 2. Provide
two openings through the interior wall, within
12 inches of the ceiling and the floor, sized per Figure 2.
Two openings — Air supply directly from outside
✷
1. Air openings must be directly through an outside wall, or into a space
that connects directly to the outside (such as a ventilated attic or crawl
space, for example).
2. See Figure 3 —
Openings directly through an outside wall — provide
two openings within 12 inches of the ceiling and the floor, sized per
Figure 3.
3. See Figure 4 —
Air supplied through vertical ducts — provide two
openings
terminated within 12 inches of the ceiling and the floor, sized
per Figure 4.
4. See Figure 5 —
Air supplied through horizontal ducts — provide
two openings within 12 inches of the floor and the ceiling, sized per
Figure 5.
Prepare boiler location — air openings
1e
Air openings must be provided
Combustion air and ventilation openings must comply with the National
Fuel Gas Code ANSI Z223.1-latest edition, or applicable local building
codes. Canadian installations must comply with B149.1 or B149.2 Instal-
lation 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.
Combustion air opening location and sizing
requirements depend on the clearances around
the boiler.
Check the boiler placement compared to
Figure 1a, page 7.
If all clearances are at least equal to Figure 1a,
page 7
, apply the sizing and placement of openings
given on pages 10 and 11.
If ANY clearance is less than Figure 1a, page 7,
you must provide air openings sized and located as
shown in Figure 1b, page 7. DO NOT apply the sizing
and location information shown on page 10 or 11.
✷
✷
✷
✷
✷
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Unusually tight construction
Unusually tight construction means (per ANSI Z223.1)
buildings in which:
a. Walls and ceilings exposed to the outside atmo-
sphere 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 such construction cases, if appliances use inside air
for combustion, provide air openings into the building
from outside
. Size and locate these openings per the
appropriate case in Figure 3, 4 or 5 on page 10.
Motorized air dampers
If the air openings are fitted with motorized dampers,
electrically interlock the damper to:
• Prevent the boiler from firing if the damper is not
fully open.
• Shut the boiler down should the damper close dur-
ing boiler operation.
To accomplish this interlock, wire an isolated contact
(proving the damper open) in series with the thermo-
stat input to the boiler. The boiler will not start if this
contact is open, and will shut down should it open
during operation.
Exhaust fans and air movers
The appliance space must never be under a negative
pressure, even if the appliance(s) are installed as direct
vent. Always provide air openings sized not only to the
dimensions required for the firing rate of all appliances,
but also to handle the air movement rate of the exhaust
fans or air movers using air from the building or space.
Single air opening option
✷
A single combustion air opening can be used in lieu of the two-opening
options on page 10, provided:
Clearances from boiler to walls
• The boiler must have clearances of at least those shown in Figure 1a,
page 7.
Opening must be directly to outside
• The opening must connect directly to the outdoors or to a space that
communicates directly to the outdoors (not to an interior space).
• The air can be provided through a direct opening or through a horizontal
or vertical duct.
Opening placement
• The top of the air opening must be within 12 inches of the ceiling.
Opening size
• The free area of the opening must be at least equal to the sum of the
area of all equipment vent connectors in the space, and . . .
• The free area of the opening must be at least 1 square inch per 3,000
Btu/hr input rating of all equipment located in the space.
FREE AREA of openings — the minimum areas
given in this manual are free area (equals the area,
length times width of opening, after deduction for
louver obstruction).
Use the free area information provided by the louver manufacturer.
When this information is not available, assume:
• Wood louvers — assume free area is 20% of total; so the actual area
of each opening with wood louvers would be 5 times the required
free area.
• Metal louvers — assume free area is 60% of actual area; so, for wood
louvers, the actual area of each opening must be 1.67 times the re-
quired free area.
Exception for large spaces
✷
No combustion air openings are needed when the boiler (and other ap-
pliances) are installed in a space with a volume at least 50 cubic feet per
1,000 Btuh
of all installed appliances, provided:
•
the building must not have unusually tight construction (see defini-
tion, this page)
• all clearances around the boiler must be no less than shown in Figure 1a,
page 7.
To determine if the space is large enough to qualify:
• Add the total input of all appliances in MBH (1,000’s of Btuh).
• Multiply this number times 50 to determine minimum room volume.
• Example: For a total input of 100 MBH (100,000 Btuh), minimum
volume is 50 x 100 = 5,000 cubic feet. At a ceiling height of 8 feet, the
space must have at least 5,000 ÷ 8 = 625 square feet (25 feet x 25 feet,
for instance).
Prepare boiler location — air openings
1e
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Inspect orifices and burners
1. Remove front jacket door. Remove base access panel
(See Figure 32, item 4, page 60).
2. Check for correctly-sized manifold orifices. See
Table 2 below for sizing. (The orifice size is stamped
on the orifice spud barrel.)
Place boiler/crate near
position
1. Leave boiler in crate and on pallet until installa-
tion 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 posi-
tion.
Do not drop boiler or bump jacket
on floor or pallet. Damage to boiler
can result.
5. Check level.
a. Shim legs, if necessary.
b. Do not alter legs.
Orifice replacement procedure
(when required)
1. Remove access panel.
2. On gas manifold, mark location of main burner with
attached pilot assembly.
3. Remove main burner with attached pilot assembly
from manifold. Remove all remaining burners.
4. Remove and discard all main burner orifices in gas
manifold.
5. Apply a small amount of pipe dope to each of the
new orifices and install in the manifold. Make sure
the orifices are aligned correctly, not cross-threaded
in the manifold tappings.
Use only pipe dope compatible with
propane gas, even if boiler is to be
operated on natural gas. Failure to
comply could result in severe per-
sonal injury, death or substantial
property damage.
6. Reinstall main burner with attached pilot assembly
at location marked on gas manifold. Reinstall all
remaining burners.
7. Follow check-out procedure, Section
7, page 33.
Table 2 Manifold orifice sizing
Correctly-sized manifold orifices
must be used. Failure to do so will
result in severe personal injury,
death or substantial property dam-
age.
3. Level and straighten burners.
Burners must be properly seated in
slots in burner rest with their open-
ings face up. Main burner orifices
must inject down center of burner.
Failure to properly seat burners
will result in severe personal injury,
death or substantial property dam-
age.
4. Reinstall access panel.
Do not operate boiler without ac-
cess panel secured in place. Failure
to comply could cause momentary
flame rollout on ignition of main
flame, resulting in possible fire or
personal injury hazard.
Location Natural gas
U.S.
0-2,000 ft.
2.00 mm
over 2,000 ft.
(Note 1)
Canada
0-2,000 ft.
2.00 mm
2,000-4,500 ft.
1.90 mm
Location Propane gas
U.S.
CGa 25
CGa 3-8
0-2,000 ft.
#61
#56
over 2,000 ft.
(Note 1)
(Note 1)
Canada
CGa 25
CGa 3-8
0-2,000 ft.
#61
#56
2,000-4,500 ft.
.95mm
#57
Note 1: For elevations above 2,000 feet, contact your
Weil-McLain sales ofce for details.
Prepare boiler — placement and setup
2a
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
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 62. 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 62-. (Use pipe dope sparingly.)
4. Connect a hose to boiler drain valve, the other end
connected to a fresh water supply. Make sure hose
can also be used to drain boiler after test.
5. Connect a nipple and shutoff valve to system supply
connection on the 1¼” tee. This valve will be used
to bleed air during the fill. (Valve and nipple are
not included with boiler.)
6. Connect a nipple and shutoff valve to system
return connection (at circulator flange if circulator
installed on return). This valve will be used to
bleed air during the fill. (Valve and nipple are not
included with boiler.)
Fill and pressure test
1. Open the shutoff valves you installed on supply and
return connections.
2. Slowly open boiler drain valve and fresh water
supply to fill boiler with water.
3. When water flows from shutoff valves, close boiler
drain valve.
Drain and remove fittings
1. Disconnect fill water hose from water source.
2. Drain boiler at drain valve or out hose, whichever
provides best access to drain. Remove hose after
draining if used to drain boiler.
3. Remove nipples and valves unless they will remain
for use in the system piping.
4. Remove plug from relief valve tapping. See Section 3
to replace relief valve.
Do not use petroleum-based clean-
ing or sealing compounds in boiler
system. Severe damage to boiler
will occur, resulting in substantial
property damage.
Leaks must be repaired at once.
Failure to do so can damage boiler,
resulting in substantial property
damage.
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 main-
tained throughout test. Check for leaks. Repair if
found.
Prepare boiler — pressure test
2b
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Prepare boiler — draft hood & spill switch2c
Draft hood installation
1. Orient draft hood with spill switch mounting holes to front of boiler
as shown in Figure 7.
2. Secure draft hood to outlet at top of boiler with sheet metal screws.
3. Bottom of draft hood or “skirt” must have clearance dimension above
jacket top panel as indicated on draft hood.
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.
Spill switch installation
1. Fasten spill switch to draft hood as shown in Figure 6
and Figure 7.
2. See Wiring diagram to connect wires:.
a. Spark-ignited pilot boiler —
see
pages 36 and 37
Improper orientation of spill switch
may cause boiler to shut down. The
loss of heat can result in significant
damage due to freezing.
Prepare boiler — install vent piping
1. Connect from draft hood or vent damper outlet to chimney or vent
with same size vent connector.
2. Where possible, vertical venting to the outside from the draft hood or
vent damper outlet will offer best performance.
3. Where horizontal vent connector is used, slope upward at least ¼” per
lineal foot toward chimney or vent and support with hangers to prevent
sagging.
4. Breeching must not be connected to any portion of a mechanical draft
system that can operate under positive pressure.
2d
Long horizontal vent connector,
excessive number of elbow or
tees, or other obstructions that
restrict the flow of combustion
gases should be avoided. Severe
personal injury, death or substan-
tial property damage could result.
Figure 7 Spill switch with wire harnessFigure 6 Install spill switch
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Prepare boiler — vent damper installation2e
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 ei-
ther end of harness is disconnected,
the system safety shutdown will oc-
cur. The boiler will not operate until
harness is reconnected.
Effikal or Field Controls damper —
Damper hold open switch must be
in Automatic Operation position
for system to operate properly.
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 58 are certified for use with CGa boilers. Any
other vent damper installed could cause severe personal
injury or death.
Installation
1. Install vent damper horizontally or vertically as
shown in vent damper manufacturer’s instructions.
Vent damper must be installed so that it serves only
one boiler and so damper blade indicator is visible
to the user. See Figure 8.
2. Screws or rivets used to secure the vent damper to
the draft hood must not interfere with rotation of
the damper blade.
3. Install damper harness between damper actuator
and knockout in jacket top panel. Use strain relief
connectors and locknuts to secure both ends of
damper harness.
Keep wiring harness clear of all hot
surfaces.
Damper blade
Spark-ignited pilot systems— Refer to vent manu-
facturer’s instructions to install plug (shipped with
damper) in damper hole. For spark-ignited pilot
boilers only, install
plug with no hole in vent damper
hole.
Minimum clearances
Provide a minimum of 6” between the vent damper and
any combustible material. (Provide a minimum of 36 "
between jacket top and combustible ceiling.)
Do not modify draft hood or vent damper, or make an-
other connection between draft hood and vent damper
or boiler except as noted below. This will void CSA
certification and will not be covered by Weil-McLain
warranty. Any changes will cause severe personal injury,
death or substantial property damage.
Figure 8 Vent damper assemblies
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Water piping — general information
General piping information
If installation is to comply with ASME or Canadian requirements, an ad-
ditional 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 36, for wiring.
Use backflow check valve in cold water supply as required by local codes.
Water temperature/LWCO sensor
A low water cutoff device is required when boiler is installed above radia-
tion level or by certain state or local codes or insurance companies. The
boiler has a pre-installed water temperature/LWCO sensor.
Pressure/temperature gauge
Install pressure/temperature gauge in tee on supply piping (as shown in
drawing on page 3).
Isolation valves
Isolation valves are required to enable servicing of the boiler’s temperature
sensor. Install as shown in appropriate piping diagram.
Relief valve
Install relief valve vertically in ¾” tapping on side of boiler. See Figure 9
or 10
, page 17, and the tag attached to the relief valve for manufacturer’s
instructions.
Chillers or air handling units:
Install boiler such that —
• Chilled medium, if used, is piped in parallel with
heating boiler. Use appropriate valves to prevent
chilled medium from entering boiler. Consult AHRI
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.
Circulator
The circulator is shipped loose (wiring pre-attached to
boiler) to allow you to locate it either in the return or
supply piping, as desired. See page 3 for a typical instal-
lation. Pipe the expansion tank to the suction side of the
circulator whenever possible. Install an air separator in
the supply piping. Connect the expansion tank to the air
separator only if the separator is on the suction side of
the circulator. Always install the system fill connection
at the same point as the expansion tank connection to
the system. Figures 9 and 10 show typical near-boiler
piping connections.
System water piping
See Figure 9 (diaphragm-type or bladder-type expansion
tank) or Figure 10 (closed-type expansion tank), 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 sys-
tems or converted gravity systems (large-volume systems
originally designed for circulation by natural convection
rather than a pump). See page 25 for boilers used with
refrigeration systems.
To avoid water damage or scalding due to relief
valve operation:
• Discharge line must be connected to relief valve outlet and run to a
safe place of disposal
. Terminate the discharge line to eliminate
possibility of severe burns should the valve discharge.
• Discharge line must be as short as possible and be the same size
as the valve discharge connection
throughout its entire length.
• Discharge line must pitch downward from the valve and terminate
at least 6” above the floor drain where any discharge will be clearly
visible.
• The discharge line shall terminate plain, not threaded, with a
material serviceable for temperatures of 375°F or greater.
• Do not pipe the discharge to any place where freezing could
occur.
• No shutoff valve shall be installed between the relief valve and
boiler, or in the discharge line. Do not plug or place any obstruc-
tion in the discharge line.
• Failure to comply with the above guidelines could result in fail-
ure 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.
Table 3 Water pipe size (based on 20°F rise)
Boiler model To
system
From
system
CGa-25
¾” ¾”
CGa-3, 4, 5
1” 1”
CGa-6, 7
1¼” 1¼”
CGa-8
1½” 1½”
Note: The boiler supply and return connections, the return/
drain tee and the supply/gauge tee supplied with
the boiler are 1¼” NPT. One of the circulator flanges
supplied with the boiler is 1¼”. The other circulator
flange is the size of the recommended system piping
shown above.
3a
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Diaphragm-type or bladder-
type expansion tank
(Figure 9)
1. Ensure expansion tank size will handle boiler and
system water volume and temperature. Tank must
be located in boiler return piping as close to boiler
as possible, before inlet side of circulator. See tank
manufacturer’s instructions for details.
2. Install an
automatic air vent as shown.
Closed-type expansion tank
(Figure 10)
1. Ensure expansion tank size will handle boiler and
system water volume and temperature. See tank
manufacturer’s instructions for details.
2. Connect tank to ½” NPT tapping located behind
supply outlet, using ½” NPT piping. Pitch any
horizontal piping up towards tank 1 inch per 5 feet
of piping.
Undersized expansion tanks cause system water to be lost from relief valve and makeup water
to be added through fill valve. Eventual section failure can result.
Water piping — single-zone system
Figure 9 Diaphragm- or bladder-type expan-
sion tank — Single-zone system using
diaphragm-type or bladder-type expan-
sion tank. See Table 3 for piping sizes.
Figure 10 Closed-type expansion tank — Single-
zone system using closed-type expan-
sion tank. See Table 3 for piping sizes.
3b
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.
Part Number 550-142-300/0520
18
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Water piping — multiple zones
Piping multiple zones
Follow instructions on pages 16 and 17 to install near-
boiler or single-zone piping. (Also refer to Piping
for radiant heating systems or converted gravity
systems,
below, if applicable.)
See
Figure 11 or Figure 12, page 19, to complete in-
stallation.
Zoning with circulators (Figure 11)
(return temp over 130°F)
1. Size each circulator to individual circuit require-
ments.
2. Do not install circulator on boiler (except for
primary/secondary piping).
3. Install isolation (balancing) valves to adjust flow to
distribute heat to all zones.
4. Install and wire a separate relay for each zone
circulator.
Zoning with zone valves (Figure 12)
(return temp over 130°F)
1. Install isolation (balancing) valves to adjust flow to
distribute heat to all zones.
2. Provide a separate 24-volt transformer to power the
zone valves. Size the transformer to handle the total
rated load of all connected zone valves.
DO NOT connect directly from
3-wire zone valves to the T-T termi-
nals on the boiler
. When using 3-wire
zone valves, install an isolation relay.
Connect the zone valve end switch wires
to the isolation relay coil. Connect the
isolation relay contact across the boiler
T-T terminals. Failure to comply can
result in damage to boiler components
or cause unreliable operation, resulting
in severe property damage.
3c
Piping for radiant heating
systems or converted gravity
systems
Converted gravity (or steam) systems
Whenever possible, use the primary/secondary piping
shown in Figures 13 or 14 on page 21. This piping de-
sign allows changing boiler flow rate without affecting
primary circuit flow rate.
If Figures 13 or 14 cannot be used, use the boiler-bypass
piping shown in Figure 15 or Figure 16 on page 23. You
can also use the piping shown in Figure 17 on page 25
(system-bypass), if the reduced flow rate in the heating
system will not cause heat distribution problems.
Failure to prevent low return water
temperature to the boiler could cause
corrosion of the boiler sections or burn-
ers, 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.
Radiant heating system piping should include a means of regulating the boiler return water
temperature and the system supply temperature (such as provided by an injection pumping
control). Boiler return water temperature will be adequately controlled using the methods
shown in this manual provided the system supply temperature is relatively constant.
DO NOT apply the methods in this manual if the system is equipped with an outdoor reset
control
. Instead, provide controls and piping which can regulate the boiler return water
temperature at no less than 130°F regardless of system supply temperature. Contact your
Weil-McLain representative for suggested piping and control methods. Failure to prevent
cold return water temperature to the boiler could cause corrosion damage to the sections or
burners, resulting in possible severe personal injury, death or substantial property damage.
Part Number 550-142-300/0520
19
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
1 Boiler isolation (balancing)
valves
2 Flow/check valve
3 System or zone circulator
5 Zone valve
6 Drain valve
9 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, page 17.)
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.
Water piping — multiple zones (continued)3c
Figure 11 Zoning with circulators — return water
130°F or higher.
Figure 12 Zoning with zone valves — return water
130°F or higher.
Part Number 550-142-300/0520
20
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
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 injec-
tion pumping control
).
Boiler return water temperature will be adequately controlled using the methods shown
in this manual provided the system supply temperature is relatively constant.
DO NOT apply the methods of this manual if the system is equipped with an outdoor reset
control.
Instead, provide controls and piping which can regulate the boiler return water
temperature
at no less than 130°F regardless of system supply temperature. Contact your
Weil-McLain representative for suggested piping and control methods.
Failure to
prevent cold return water temperature to the boiler could cause corrosion
damage to the sections or burners, resulting in possible severe personal injury, death or
substantial property damage.
Primary/secondary (preferred)
Bypass piping method
Primary/secondary bypass piping is preferred because
the flow rate and temperature drop in the heating
circuit(s) is determined only by the heating circuit
circulator(s). So adjustment of the bypass valves in
the boiler circuit will not cause a change in the heating
circuit rate and temperature distribution.
Figures 13 and 14, page 21, 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
3d
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/pres-
sure gauge reads at least 150°F when the system return
water is cold (approximately 60°F water temperature).
Valve adjustment
(Figures 13 and 14 on
ly)
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 tempera-
ture 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 wa-
ter from the boiler supply which mixes with return
water. Valve 7b regulates the amount of system water
flowing through the boiler secondary loop.
Water piping — low temperature systems
Part Number 550-142-300/0520
21
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
1 Boiler isolation (balancing) valves
2 Flow/check valve
3 System or zone circulator (circulator should cycle
with zone valve and switches, using circulator valve
or zone control panel)
4 System temperature gauges
5 Zone valve
6 Drain valve
7 System temperature valves (see instructions to the
left for adjusting valves)
8 Blend temperature gauge
9 Relief valve
10 Automatic air vent (with diaphragm-type expansion
tank), or connect to tank fitting (closed-type expan-
sion 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,
page 17.)
13 Air separator and automatic vent, if used (Note that
the fill valve must always be connected to the expan-
sion tank, regardless of location of expansion tank,
circulator or air separator.)
Figure 13 Primary/secondary piping
Zoning with circulators
Figure 14 Primary/secondary piping
Zoning with zone valves
Water piping — low temperature systems (continued)3d
Part Number 550-142-300/0520
22
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
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 injec-
tion 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.
BOILER-bypass piping
method
This piping method (Figure 15 or 16, page 23) 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,
page 25, 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, help-
ing to equalize the building heat distribution.
Temperature gauges
Gauge 4a is optional if the bypass valves will be ad-
justed 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.
Water piping — low temperature systems (continued)3d
Part Number 550-142-300/0520
23
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
1 Boiler isolation (balancing) valves
2 Flow/check valve
3 System or zone circulator
4 System temperature gauges
5 Zone valve
6 Drain valve
7 System temperature valves (see instructions
to the left for adjusting valves)
8 Blend temperature gauge
9 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.)
13 Air separator and automatic vent, if used (Note that the
fill valve must always be connected to the expansion
tank, regardless of location of expansion tank, circulator
or air separator.)
Figure 15 Boiler-bypass piping
Zoning with circulators
(Alternative to primary/secondary piping
Figures 13 and 14)
Figure 16 Boiler-bypass piping
Zoning with zone valves
(Alternative to primary/secondary piping
Figures 13 and 14)
Water piping — low temperature systems (continued)3d
Part Number 550-142-300/0520
24
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
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.
Water piping — low temperature systems (continued)
SYSTEM-bypass piping
method
This piping method (Figure 17, page 25) is called a
system-bypass because part of the circulator flow by-
passes 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 regulat-
ing the water temperature provided to the system and
could result in excessive water temperature in the radi-
ant 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).
3d
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
3 System or zone circulator
7 System temperature valves (see instructions to the left for
adjusting valves)
8 Blend temperature gauge
9 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
, page 17.)
Figure 17 System-bypass piping — Zoning with
zone valve or circulators, return water
130°F or higher — (Alternative to boiler-
bypass piping Figures 15 and 16,
page 23)
Figure 18 Piping refrigeration systems
Prevent chilled water from
entering boiler
Water piping — refrigeration systems3e
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.
If boiler is connected to heating coils located in air han-
dling units where they can be exposed to refrigerated
air, use flow control valves or other automatic means to
prevent gravity circulation during cooling cycle.
Water piping — low temperature systems (continued)3d
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
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.
Connect gas supply piping to boiler
1. Remove jacket front panel and refer to Figure 19 to pipe gas to boiler.
a.
Install drip leg at inlet of gas connection to boiler. Where local
utility requires drip leg to be extended to the floor, use appropri
-
ate length of pipe between cap and tee.
b.
Install ground joint union for servicing, when required.
c.
Install manual shutoff valve in gas supply piping outside boiler
jacket when required by local codes or utility requirements.
d.
In Canada — When using manual main shutoff valve, it must be
identified
by the installer.
2.
Support piping with hangers, not by boiler or its accessories.
3.
Purge all air from gas supply piping.
4. Before placing boiler in operation,
check boiler and its gas connec-
tion for leaks
.
a. Close manual main shutoff valve during any pressure testing at
less than 13” w.c.
b.
Disconnect boiler and gas valve from gas supply piping dur-
ing any pressure testing greater than 13” w.c.
Do not check for gas leaks with an open flame —
Use bubble test. Failure to use bubble test or check for
gas leaks can cause severe personal injury, death or
substantial property damage.
5.
Use pipe dope compatible with propane gases. Apply sparingly only
to male threads of pipe joints so that pipe dope does not block gas flow.
Failure to apply pipe dope as detailed above can result
in severe personal injury, death or substantial property
damage.
Gas piping
Figure 19 Gas supply piping
Table 4 Pipe capacity for 0.60 specific gravity natural gas
4
Gas pipe
length
(feet)
Capacity of pipe for pipe size of:
(Capacity in cubic feet gas per hour)
½” ¾” 1” 1¼” 1½”
10 132 278 520 1050 1600
20 92 190 350 730 1100
30 73 152 285 590 860
40 63 130 245 500 760
50 56 115 215 440 670
75 45 93 175 360 545
100 38 79 150 305 460
150 31 64 120 250 380
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
For your safety, turn off electrical power supply at ser-
vice entrance panel before making any electrical con-
nections
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.
Installation must comply with:
1. National Electrical Code ANSI /NFPA 70 – latest edition
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 36 for spark-ignited pilot boiler.
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 equip-
ment 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 37.
For other devices, refer to manufacturer’s specifica-
tions. Wiring diagram on boiler gives setting for
control module and gas valve. Also see instructions
with thermostat.
DHW
Connect DHW aquastat as shown in wiring below.
Economy function isn’t utilized with DHW input.
Junction box (furnished)
1. Connect 120 VAC power wiring (Figure 20).
2. Fused disconnect or service switch (15 amp. recom-
mended) may be mounted on this box. For those
installations with local codes which prohibit instal-
lation 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.
DO NOT connect directly from 3-wire
zone valves to the T-T terminals on
the boiler
. When using 3-wire zone
valves, install an isolation relay. Connect
the zone valve end switch wires to the
isolation relay coil. Connect the isolation
relay contact across the boiler T-T
terminals. Failure to comply can result in
damage to boiler components or cause
unreliable operation, resulting in severe
property damage.
Field wiring
Figure 20
Field wiring connec-
tions —
service switch, DHW
(if used) and
thermostat
(or end switch) pro-
vided by installer
5
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Start-up — preparation6a
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 detect-
able. 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.
• 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 clean-
ing 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 wa-
ter 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. Inhib-
ited propylene glycol is recommended.
Do not use ethylene glycol, automo-
tive 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 65.
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.
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — 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 Fig-
ure 16
). Route hose to an area where water can
drain and be seen.
b. Close the boiler or system isolation valve be-
tween 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 pro-
ceed 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, elimi-
nate 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, begin-
ning 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.
Start-up — preparation (continued)
6a
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.
Inspect base insulation
The boiler contains ceramic fiber
and fiberglass materials. Use care
when handling these materials
per instructions on page 66 of this
manual. Failure to comply could
result in severe personal injury.
Failure to replace damaged in-
sulation or reposition insulation
can result in a fire hazard, causing
severe personal injury, death or
substantial property damage.
Check to make sure
base insulation is secure against
all four sides of the base. If insulation is damaged or
displaced, do not operate boiler. Replace or reposition
insulation.
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Start-up — operate boiler
6b
• Read manual Section 9 and the 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 Operating instruction location guide
Models Spark-ignited pilot Gas Page
CGa-25
to
CGa-6
Honeywell VR8204/VR8304 Natural/Propane
38
Robertshaw 7200 Natural 39
White-Rodgers 36E Natural 40
CGa-7
&
CGa-8
Honeywell VR8204/VR8304 Natural/Propane 38
White-Rodgers 36C Natural 41
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, do the following:
Adjust boiler control settings
BOILER OPERATING TEMPERATURE
With power turned on, control module receives a signal from
the temperature/LWCO sensor and displays boiler temperature.
The control knob labeled BOILER TEMP is used to adjust the
operating temperature setpoint, turning clockwise to increase
temperature setting and counterclockwise to decrease. When the
knob is turned to adjust temperature the display will brighten to
indicate adjustment mode. After temperature is set to desired
value, display will dim after approximately 5 seconds to indicate
measurement mode.
• ADJUST BOILER OPERATING TEMPERATURE TO
DESIRED SETPOINT.
BOILER ECONOMY SETTING
To comply with Department of Energy regulations, the control
module circulates available hot water before turning on the boiler
to attempt to satisfy a call for heat. While attempting to satisfy
the heat demand, the control module also monitors the boiler
temperature changes via the temperature/LWCO sensor and
determines whether or not the available hot water will satisfy the
demand, adjusting the time delay to turn on the boiler until it
determines that additional heat will be needed. The knob labeled
ECONOMY ADJUST provides an adjustment between maximize
(MAX) and minimize (MIN) time delay. The maximum (MAX)
adjustment position should be used to maximize energy savings.
Turning the knob counterclockwise decreases the delay time and
should only be used in the event that the heated space becomes
uncomfortable.
• ADJUST ECONOMY TO DESIRED POSITION (MAX IS
THE PREFERRED SETTING).
IMPORTANT
In accordance with Section 325 (f) (3) of the Energy Policy and
Conservation Act, this boiler is equipped with a feature that saves
energy by reducing the boiler water temperature as the heating
load decreases. This feature is equipped with an override which
is provided primarily to permit the use of an external energy
management system that serves the same function.
THIS OVERRIDE MUST NOT BE USED UNLESS AT LEAST
ONE OF THE FOLLOWING CONDITIONS IS TRUE:
• An external energy management system is installed that
reduces the boiler water temperature as the heating load
decreases.
• This boiler is part of a modular or multiple boiler system
having a total input of 300,000 BTU/hr or greater.
• This boiler is equipped with a tankless coil.
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Start-up — operate boiler (continued)6b
Start-up — if boiler doesn’t start . . .6c
Check for:
Eliminate all system leaks.
Continual fresh makeup water
will reduce boiler life. Minerals
can build up in sections, reduc-
ing 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 immedi-
ately. Do not start boiler again
until corrected. Failure to comply
could result in severe personal
injury, death or substantial prop-
erty damage.
Do not use petroleum-based
cleaning or sealing compounds
in boiler system. Severe damage
to boiler will occur, resulting in
substantial property damage.
4. Gas not turned on at meter or boiler?
5. Incoming gas pressure less than:
5” w.c. for natural gas? 11” w.c. for propane gas?
6. If none of the above corrects the problem, refer to
Troubleshooting, Section 11 of this manual.
1. Loose connections, blown fuse or service switch off?
2. Boiler temperature adjustment set below boiler
water temperature?
3. Thermostat set below room temperature?
Start the boiler
• Follow the Operating Instructions from Section
9
to start the boiler. Remove boiler jacket door and
note the gas valve manufacturer and model number.
Use only the operating instruction which applies to
this gas valve (see Table 5, page 30). (The operating
instruction label on the boiler provides the same
information.)
• See
Section 6c if boiler fails to start.
Check system and boiler
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 of this manual.
5.
Verify operation per Section 6d. Perform check-out
procedure in Section 7 and fill in the Installation
and service certificate
on the same page.
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
See Section 9 for operation and operating information.
Figure 21 Typical pilot burner flame
Figure 22 Typical main burner flame
Check vent system operation
1. Check vent system at least once a month during
heating season. With boiler firing, hold candle or
match below lower edge of draft hood “skirt”. If
flame does not blow out, but burns undisturbed,
vent system is functioning properly. If flame blows
out or flickers drastically, inspect vent system for
obstructions or other causes of improper venting
(such as exhaust fans in boiler room).
Check burner flames
Pilot burner flame (Figure 21)
PROPER pilot flame
1. Blue flame.
2. Inner cone engulfing pilot flame sensor (spark-
ignited pilot).
3. Pilot flame sensor glowing cherry red.
IMPROPER pilot flame
1. Overfired — Large flame lifting or blowing past pilot
flame sensor.
2. Underfired — Small flame. Inner cone not engulfing
pilot flame sensor.
3. Lack of primary air — Yellow flame tip.
Main burner flame (Figure 22)
PROPER main burner flame
1. Yellow-orange streaks may appear (caused by dust).
IMPROPER main burner flame:
1. Overfired — Large flames.
2. Underfired — Small flames.
3. Lack of primary air — Yellow tipping on flames
(sooting will occur).
Check vent damper operation
1. Raise room thermostat to call for heat — Vent
damper actuator will slowly open vent damper.
2. When vent damper is fully open — Pilot will light,
then allow main burners to ignite.
Vent damper must be fully open
before main burners light. If vent
damper does not fully open, flue
products such as carbon monoxide
will escape into house, causing se-
vere personal injury or death.
3. Lower thermostat setting — Main burner flames
will go out, then vent damper will close.
4. Repeat Steps 2 through 4 several times to verify
operation.
5. Return thermostat to normal setting.
6. Set thermostat heat anticipator setting indicated on
wiring diagram.
Start-up — verify operation
6d
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Installation and service certificate
Boiler model ______________ Series _______ Consumer Protection number _____________ Date installed ___________
Measured Btuh input ____________________
Installer ________________________ ________________________________ ________________________
(company) (address) (phone)
Installer’s signature: _____________________________________
❏ 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
Check-out procedure — checklist7
❏ 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.
Correctly sized manifold orifices must be used.
Failure to do so will cause severe personal
injury, death or substantial property damage.
❏ Followed operating instructions on boiler or in manual
Section
9 for proper start-up?
❏ Proper burner flame observed? Refer to
Check burner flame,
manual Section 6d.
❏ Test temperature limit — While burners are operating, turn
Boiler Temp adjustment knob counterclockwise until display
reading is below actual boiler water temperature. Burners
should go off while circulator continues to operate. Turn
Boiler Temp adjustment knob clockwise until display read-
ing is above boiler water temperature and ignition sequence
should resume.
❏ Test low water cut off – While burners are operating, press
and hold “LWCO TEST” button on control. Burners should
go off while circulator continues to operate and LWCO light
should turn ON. Release “LWCO TEST” button and ignition
sequence should resume.
❏ Test field-installed controls — If the boiler has an additional
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.
❏ Button on spill switch pushed in?
❏ Test ignition system safety device
Connect manometer to outlet side of gas valve. Start boiler,
allowing for normal start-up cycle to occur and main burn-
ers to ignite. With main burners on, manually shut off gas
supply at manual main shutoff gas valve. Burners should go
off. 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 Boiler Temp adjustment knob to system temperature re-
quirements. Adjust balancing valves and controls to provide
design temperature to system.
❏ Set Economy mode, fully clockwise.
❏ For multiple zones, adjust flow so it is about the same in
each zone.
❏ 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.
❏ Cycle DHW Aquastat if used.
❏ Measure natural gas input:
a. Operate boiler 10 minutes.
b. Turn off other appliances.
c. At natural gas meter, measure time (in seconds) re-
quired to use one cubic foot of gas.
d. Calculate gas input:
3600 x 1000
number of seconds from step c
= Btuh
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 pres-
sure 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.
Part Number 550-142-300/0520
34
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Operation — spark-ignited pilot boilers9a
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 de-energized. No gas flows to pilot or main gas valve.
2.
Call for heat (thermostat circuit closes):
a. While attempting to satisfy the heat demand, the control
module monitors the boiler temperature changes via the
temperature sensor and determines whether or not the
available hot water will satisfy the demand, only running
the circulator. If additional heat is needed, the sequence
continues. When DHW (if used) calls for heat, sequence
above is bypassed.
b. Vent damper and circulator energized if pilot status ac-
ceptable. Vent damper drives open. When vent damper end
switch makes circuit, ignition control begins pilot ignition
attempt.
c. 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. Natural Gas - If pilot does not light within 15 seconds,
pilot valve 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.
c. Propane Gas - If pilot does not light within 15 seconds,
pilot valve is closed and spark generator is turned off. Control
module waits 1 minute then attempts to ignite pilot again.
After first failed ignition retry attempt, control module will
attempt to ignite pilot 2 more times with a 5 minute wait
period after the second try and a 60 minute wait period after
the third try. If the ignition control does not sense pilot flame
during these trials, it will lock out the boiler and require a
manual reset procedure to allow further attempts.
Manual Reset Procedure for Propane Gas Lockout ––
Unburned propane gas may have accumulated
in combustion chamber. Provide adequate
ventilation to completely remove any
accumulated LP gas from boiler and adjacent
area before attempting to reset and light boiler.
Failure to do so will cause severe personal
injury, death or substantial property damage.
Propane Gas Lockout manual reset – ONLY
after boiler area has been cleared of any
accumulated LP gas:
• Push and hold TEST button, see page 50, Item 11.
• While holding TEST button, rotate Economy Adjust knob
fully clockwise then fully counter clockwise.
• Release TEST button.
• Control module is reset.
This boiler is equipped with a control system that automatically adjusts a time delay period to turn on the boiler during a call
for heat. This is accomplished by circulating available hot water in the system while measuring water boiler water tempera-
ture changes. The control calculates a suitable delay based on temperature measurements and turns the boiler on only after it
determines that the demand for heat cannot be satisfied with the available hot water,
Due to the wide variety of controls used in boiler installations, this control is also equipped with an adjustment for the cal-
culated time delay period (ECONOMY ADJUST). In the MIN position, the time delay is zero and the IMPORTANT notice
below must be observed:
IMPORTANT
In accordance with Section 325 (f) (3) of the Energy Policy and Conservation Act, this boiler is equipped with a feature that
saves energy by reducing the boiler water temperature as the heating load decreases. This feature is equipped with an override
which is provided primarily to permit the use of an external energy management system that serves the same function.
THIS OVERRIDE MUST NOT BE USED UNLESS AT LEAST ONE OF THE FOLLOWING CONDITIONS IS TRUE:
• An external energy management system is installed that reduces the boiler water temperature as the heating load
decreases.
• This boiler is part of a modular or multiple boiler system having a total input of 300,000 BTU/hr or greater.
• This boiler is equipped with a tankless coil.
Department of Energy – Compliance
8
Part Number 550-142-300/0520
35
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Figure 24 Ignition control module sequence of operation — status light indications
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 de-energized, 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 37.
Operation — spark-ignited pilot boilers
9a
STEPS
(following step 7, cycle goes back to step 1.)
Call for
Heat?
POWER TSTAT
CIRC
LIMIT DAMPER FLAME LWCO
Timing
1. Standby
• Waiting for call for heat
NO
—
2. Call for heat
• Circulator on
YES —
3. Limit circuit
• Limit controls closed
YES —
4. Damper circuit
• Damper proven open
YES —
5. Flame proven *
• Gas valve open
• Ignitor remains on
• Boiler producing heat
YES 15 sec
6. Limit cycle
• Limit circuit open
• Gas valve closed
YES —
7. Flame outage *
• Flame out
• Boiler recycles
YES
—
8. Thermostat satisfied
• Circulator off
NO
—
9. Circulator exercise routine
• Circulator turns on for 30 seconds if
boiler not operated for 30 days
NO
30 sec
10. LWCO circuit
• LWCO circuit open
YES/NO —
= ON
= OFF
* See Section 9, Items 3b and 3c for controls response to failure to prove pilot flame.
Control will lockout under the following conditions:
• Line voltage polarity is reversed
• Stray voltage is sensed on thermostat line
• Damper end switch not proven within 5 minutes from thermostat
call for heat
• Flame is sensed when it shouldn’t be there
Control will reset after these lockouts :
• 1 hour waiting period
• Opening and closing of thermostat circuit for 2 to 20 seconds
• Removal of 120 VAC power for 2 to 20 seconds
O
BL
BL
TSTAT
SENSORLWCO
TEST
OUTDOOR
COMM
BK
Y
C
BK
R
R
BK
G
R
Y
DO NOT connect directly from 3-wire zone valves to the T-T terminals on the
boiler. When using 3-wire zone valves, install an isolation relay. Connect the zone valve
end switch wires to the isolation relay coil. Connect the isolation relay contact across the
boilerT-T terminals. Failure to comply can result in damage to boiler components or
cause unreliable operation, resulting in possible severe property damage.
CAUTION
• The control module is polarity-sensitive to the incoming 120 VAC power. If polarity is
reversed, control will flash the light when powered and will not cycle boiler.POWER
•All contacts shown without power applied.
•Connector and status light locations/orientations may vary.
NOTICE
59374b +LWCO
Items not
provided
FIELD
WIRING
SERVICE
SWITCH
Junction box,
boiler left side
Jacket opening,
boiler left side
Black
White
Green
Ground
screw
Wire nuts
Black
Black
120 VAC—
Neutral
Hot
Gnd
W
BK
BR/Y
"C"
"A"
W
W
R
TRANSFORMER
TEMPERATURE/
LWCO SENSOR
PILOT
BURNER
GAS VALVE
CIRCULATOR
Terminal block
OFF
ON
W
Y
(Honeywell VR8204 shown)
80
60
70
80
70
60
THERMOSTAT
TRANSFORMER
POWER
CIRC
POWER
LIMIT
DAMPER
FLAME
LWCO
TSTAT/
CIRC
PILOT MAIN
FIELD
WIRING
O
BK
Y
ROLLOUT
TFE
Additional
limits,if used
(note 7)
Y
"B"
R
R
W
PK/BL
G
BK
W
To DHWAquastat
(if used)
To
Ground
Screw
BL
G
BK BK
OUTDOOR
TEMPERATURE
SENSOR
(if used)
SPILL SWITCH
Y
BK
1
2
3
4
VENT DAMPER
G
R
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Operation — spark-ignited pilot system (continued)9a
Figure 25a Schematic wiring diagram — Spark-ignited pilot system
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 manufac-
turer's instructions and this manual for applica-
tion and wiring suggestions.
6. Refer to control component instructions
packed with the boiler for application informa-
tion.
7. Wire any additional limit controls (low water
cut-off, additional high limit, etc.) in series with
boiler rollout TFE and spill switch as shown.
Honeywell VR8204
Honeywell VR8304
White-Rodgers 36E
White-Rodgers 36C
*Terminals 2–4 are factory-jumpered on the
White-Rodgers 36C gas valve.
MV/PV
MV/PV
2
2–4 *
MV
MV
1
1
PV
PV
3
3
Table G: Gas valve terminals and anticipator settings
Gas valve
"A""B" "C"
Anticipator
amps
0.6
0.8
0.64
0.7
Electrical shock hazard — can
cause severe injuryor death.
Disconnect power before installing
or servicing.
WARNING
Legend for ladder wiring diagram
120 VAC factory wiring
High voltage spark ignition wiring
Low voltage factory wiring
Ground connectors
120 VAC field wiring
Low voltage field wiring
59374a+LWCO
SERVICE
SWITCH
THERMOSTAT
120 VAC
24 VAC
Control Module
LowVoltage Section
CONTROL
MODULE
120 VAC
SECTION
ROLLOUT
TFE
Additional
limits (note 7)
CIRCULATOR
PILOT GAS
VALVE
MAIN GAS
VALVE
TEMPERATURE
LWCO SENSOR
PILOT FLAME
SENSOR
PILOT
IGNITION
ELECTRODE
HIGH
VOLTAGE
HIGH
VOLTAGE
120 VAC
GndNeutralHot
See Table G
"A"
"C"
"B"
Power
Tstat–Circ
Limit
Damper
Flame
R
R
R
R
R
Outdoor Temperature
Sensor (if used)
SPILL
SWITCH
DAMPER END SWITCH
(INTERNAL TO DAMPER)
VENT
DAMPER
24 VAC
CALL
FOR HEAT
24 VAC
CONSTANT
LWCO
R
DHW (if used)
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Figure 25b Ladder wiring diagram — Spark-ignited pilot system
Operation — spark-ignited pilot system (continued)9a
• Spark pilot • Natural gas • Propane gas
• Gas valve: Honeywell VR8204/VR8304
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
9b Operating instructions
CGa-25 to CGa-8
• Spark pilot • Natural gas
• Gas valve: Robertshaw 7200
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
9b
Operating instructions
CGa-25 to CGa-6
• Spark pilot • Natural gas
• Gas valve: White-Rodgers 36E
Part Number 550-142-300/0520
40
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
9b
Operating instructions
CGa-25 to CGa-6
• Spark pilot • Natural gas
• Gas valve: White-Rodgers 36C
Part Number 550-142-300/0520
41
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
9b
Operating instructions
CGa-7 to CGa-8
Part Number 550-142-300/0520
42
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
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.
Service technician
(see following pages for instructions)
Owner maintenance
(see CGa User’s Information Manual for instructions)
A
nnuAl
stArt
-
up
Inspect:
• Reported problems
• Boiler area
• Air openings
• Flue gas vent system
• Pilot and main burner flames
• Water piping
• Boiler heating surfaces
• Burners and base
• Condensate drain system
Service:
• Oiled-bearing circulators
• Temperature/LWCO sensor
Start-up:
• Perform start-up per manual
Check/test:
• 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
Daily
• Check boiler area
• Check air openings
• Check boiler pressure/
temperature gauge
Monthly
• Check boiler interior piping
• Check venting system
• Check air vents
• Check boiler relief valve
• Check condensate drain system
• Check automatic air vents (if
used)
Periodically
• Test low water cutoff
Every 6 months
• Operate relief valve
End of season
• Shut down procedure
Service and maintenance — schedule10a
VERIFY PROPER OPERATION AFTER SERVICING
Table 6 Service and maintenance schedules (service technician and user)
Part Number 550-142-300/0520
43
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Service & maintenance — annual start-up10b
❏ Inspect . . .
Reported problems
Inspect any problems reported by owner and correct
before proceeding.
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 open-
ings 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 boiler vent discharge and air intake are
clean and free of obstructions.
Flue gas vent system
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.
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 pip-
ing for signs of leaks.
2. Repair any leaks before proceeding.
The boiler should be inspected and started annu-
ally
, 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, page 42, and explained on the follow-
ing 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.
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.
Do not use petroleum-based cleaning or sealing
compounds
in boiler system. Severe damage to
boiler will occur, resulting in substantial property
damage.
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.
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Service & maintenance – annual start-up (cont.)10b
❏ Inspect . . .
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
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
The boiler contains ceramic
fiber and fiberglass materials.
Use care when handling these
materials per instructions on
page 66 of this manual. Failure
to comply could result in severe
personal injury.
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.
1. After turning off power to the boiler, remove the
jacket door and base access panel (Figure 32, item 4,
page 60).
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 66
regarding working with insulation materials.
b. Verify that the insulation is intact and secure
against all four sides of the base.
❏ Service . . .
Oiled-bearing circulators
1. The circulator shipped with the CGa boiler is water-
lubricated. 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.
Temperature/LWCO sensor
1. The temperature/LWCO sensor may accumulate
deposits on the probe surface. Annual inspection
and cleaning of the probe will improve boiler
performance.
Disconnect power, unplug harness from sensor.
a. Drain boiler water to a level below the sensor.
b. Remove sensor from boiler.
c. Wipe any built up contaminates from probe
and insulator surfaces.
d. Reinstall sensor into boiler using appropriate
thread sealant. Do not overtighten.
e. Refill boiler.
❏ Start-up . . .
1. Perform all start-up procedures given in Section 6
of this manual.
2. Verify cold fill pressure is correct and that fill
system is working properly.
3. Verify antifreeze level (if used) is at the right con-
centration and that inhibitor level is correct.
4.
Check gas piping, per manual Sections 4 and 6,
verifying no indications of leakage and all piping
and connections are in good condition.
5. Read the Operating instructions (manual
Section 9 ) applying to the boiler.
6. Start the boiler following appropriate Operating
instructions
(manual Section 9).
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
❏ Check/test
Gas piping
1. Sniff near floor and around boiler area for any in-
dication of a gas leak.
2. Test gas piping using bubble test, per Section 4
of this manual, if there is any indication of a leak.
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 expan-
sion tank.
Air vents and air elimination
1. Inspect automatic air vents (if used). Also inspect
air separators to ensure they are operational.
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.
Figure 26 Automatic air vent, typical
Limit controls and cutoffs
1. Inspect and test the boiler limit control. Verify op-
eration by turning control set point below boiler
temperature. Boiler should cycle off. Return dial to
original setting.
2. Inspect and test additional limit controls or low
water cutoffs installed on system.
Service & maintenance – annual start-up (cont.)10b
Expansion tank
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 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 circula-
tion 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 pres-
surizing 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 lo-
cated on top of an air eliminator, as shown in
examples in manual Section 3.
2. If relief valve has tended to weep frequently, the
expansion tank may be waterlogged or undersized.
Closed-type tank — tank is most likely water-
logged. 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 neces-
sary to provide sufficient expansion. If tank size is
large enough, remove tank from system and check
charge pressure (usually 12 psig for residential ap-
plications). If tank won’t hold pressure, membrane
has been damaged. Replace tank.
Part Number 550-142-300/0520
46
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
2. After following the above warning directions, if the relief valve
weeps or will not seat properly, replace the relief valve. Ensure
that the reason for relief valve weeping is the valve and not over-
pressurization of the system due to expansion tank waterlogging
or undersizing.
Figure 27 Relief valve, typical
❏ Review with owner
1. Review the User’s Information Manual with the owner.
2. Emphasize the need to perform the maintenance schedule speci-
fied in the User’s Information Manual (and in this manual as
well).
3. Remind the owner of the need to call in a licensed 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.
❏ Cleaning boiler heating
surfaces
The boiler contains ceramic fiber and fiberglass
materials. Use care when handling these materials
per instructions on page 66 of this manual. Failure
to comply could result in severe personal injury.
1. Shut down boiler:
• Follow “To Turn Off Gas to Appliance” instructions on boiler
and Operating instructions.
• Do not drain boiler unless it will be exposed to freezing tem-
peratures. 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.
Safety relief valves should be rein-
spected AT LEAST ONCE EVERY
THREE YEARS
, by a licensed plumb-
ing contractor or authorized inspection
agency, to ensure that the product has
not been affected by corrosive water
conditions and to ensure that the valve
and discharge line have not been altered
or tampered with illegally. Certain
naturally occurring conditions may
corrode the valve or its components
over time, rendering the valve inopera-
tive. Such conditions are not detectable
unless the valve and its components are
physically removed and inspected. This
inspection must only be conducted by
a plumbing contractor or authorized
inspection agency — not by the owner.
Failure to reinspect the boiler relief
valve as directed could result in unsafe
pressure buildup, which can result in
severe personal injury, death or sub-
stantial property damage.
Following installation, the valve lever
must be operated AT LEAST ONCE
A YEAR
to ensure that waterways are
clear. Certain naturally occurring min-
eral deposits may adhere to the valve,
rendering it inoperative. When manu-
ally operating the lever, water will dis-
charge and precautions must be taken
to avoid contact with hot water and to
avoid water damage. Before operating
lever, check to see that a discharge line
is connected to this valve directing the
flow of hot water from the valve to
a proper place of disposal otherwise
severe personal injury may result. If
no water flows, valve is inoperative.
Shut down boiler until a new relief
valve has been installed.
Service & maintenance – annual start-up (cont.)10b
❏ Check/test (continued)
Boiler relief valve
1. Inspect the relief valve and lift the lever to verify flow as
in the following warnings, excerpted from a relief valve
manufacturer’s warning label. Before operating any
relief valve, ensure that it is piped with its discharge in
a safe area to avoid severe scald potential. Read manual
Section 3 before proceeding further.
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Service & maintenance – annual start-up (cont.)10b
❏ Cleaning boiler heating surfaces (continued)
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 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 of this manual and the
boiler Operating instructions (Section 9b). Excessive sooting
indicates improper gas combustion. If found, check for proper
combustion and make any necessary adjustments.
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.
Troubleshooting — components11a
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 Trouble-
shooting Charts
. Severe personal injury,
death or substantial property damage can
result.
Burner access panel must be in position
during boiler operation to prevent mo-
mentary flame rollout on ignition of main
flame. Severe personal injury or substantial
property damage will result.
See pages 48 through 56 for additional
troubleshooting information.
Sensor resistance values
Temp
(°F)
Sensor ohms
Temp
(°F)
Sensor ohms
Min Max Min Max
32
34265 37871
120
4517 4992
40
27834 30764
130
3698 4088
50
21630 23907
140
3043 3364
60
16944 18727
150
2517 2782
70
13372 14780
160
2091 2311
80
10629 11747
170
1744 1928
90
8504 9399
180
1461 1615
100
6847 7568
190
1229 1359
110
5545 6129
200
1038 1147
Temperature/LWCO sensor
1. The boiler temperature/LWCO sensor is a resistance-type
device.
2. The Table 7, below shows the correct value for the sensor at
various temperatures.
3. Use the resistance values at 32°F, 60°F, 70°F and 212°F to
measure the sensor resistance at known temperatures (ice
point, room temperature and sea level boiling point). For ice
point and boiling point, insert the sensor in water at that tem-
perature. Use an ohmmeter to read resistance value between
thermister # and thermistor common. See Figure 30, page 50,
for sensor plug details.
Table 7 Temperature/LWCO sensor resistance values
Part Number 550-142-300/0520
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Troubleshooting — procedure (continued)
Check the following:
1. Wire connectors to control module are securely
plugged in at module and originating control.
2. Gas pressures:
a. With boiler off — 13” w.c. maximum natural
or propane gas pressure upstream of gas valve.
b. With boiler on:
• 5” w.c. minimum natural gas pressure or
11” w.c. propane gas pressure upstream of
gas valve.
• 3.5” w.c. minimum natural gas pressure or
10” w.c. propane gas pressure downstream
tapping on gas valve — Can be adjusted by
regulator on gas valve.
In event of vent damper
failure:
Effikal or Field Controls damper
If troubleshooting chart recommends replacing actua-
tor and actuator is not immediately available, damper
blade can be fixed in an open position to allow boiler
operation. Manually turning blade can cause actuator
damage. Follow these instructions only in case of no
heat or damper actuator malfunction.
1. Move damper service switch to
Hold Damper Open
position. Apply call for heat to boiler. Damper blade
should then rotate to open position and boiler will
fire.
2. If step 1 does not open damper, manually rotate
damper blade to open position using wrench or
• Verify proper operation after servicing. • See vent damper manufacturer’s instructions packed with vent damper
for additional information. Failure to comply could result in severe personal injury, death or substantial property
damage.
Figure 28 Manually
opening the
vent damper
pliers on flat shaft between damper and actuator.
Boiler will fire. Verify that damper service switch is
in Hold Damper Open position. (Figure 28)
3.
Do not leave vent damper permanently in this
position.
Replace actuator immediately. If vent
damper is left in open position, boiler will not oper-
ate at published efficiencies.
If troubleshooting chart recommends replacing actua-
tor and actuator is not immediately available, damper
blade can be fixed in an open position to allow boiler
operation. Follow these instructions only in case of no
heat or damper actuator malfunction. See
Figure 28.
1. Turn off power to boiler.
Failure to turn off power to boiler can
result in severe personal injury, death
or substantial property damage.
2. Refer to vent damper manufacturer’s instructions
for procedure to fix vent damper in open position.
3. Turn on power to boiler.
4. Using wrench or pliers on flat shaft section, manu-
ally rotate damper blade until green light turns on.
Boiler will fire. (
Figure 28)
5. Do not leave vent damper permanently in this posi-
tion. Replace actuator immediately. If vent damper
is left in open position, boiler will not operate at
published efficiencies.
11a
Part Number 550-142-300/0520
49
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Figure 29 CGa/EG Ignition control module
The information on this page and
pages 50 through 57 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 1 through 7, pages
51- 57, help you identify problems
based on indicator light condi-
tions.
Troubleshooting — spark-pilot boilers
11b
Control module
Solder or water splatter be-
tween 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.
Make sure ground wiring is in-
stalled per wiring diagram. Good
grounding is extremely important
for proper operation.
Control indicator lights —
HARD LOCKOUT Summary (Flashing LED’s)
MAY remove 120 VAC power for more than 2 seconds to clear lockout OR
ignition control will automatically restart sequence of operation after 1 hour
waiting period after fault condition is cleared.
INDICATOR LIGHT
CONDITION
POWER
Flashes once per second
120 VAC connection to boiler
reversed or there is insufcient
earth ground.
Flash code 2* Internal fault, microprocessor or
memory.
Flash code 3* Internal fault, LWCO circuit.
Flash code 4* Unused.
Flash code 5* Internal fault, water thermistors
disagree.
Flash code 6*
Flashes once per second
Internal fault, gas valve circuit.
* Flash code pattern: POWER LED ashes 2, 3, etc. times
rapidly followed by 2 seconds off, then repeats.
ALL LED’S FLASHING Failure to establish pilot
ame after 4 attempts.
SOLID LWCO LED Low water condition occurred.
SOFT LOCKOUT Summary (Flashing LED’s)
MAY remove 120VAC power for more than 2 seconds, cycle thermostat for
between 2 and 20 seconds, OR ignition control will automatically restart
sequence of operation after 1 hour waiting period.
INDICATOR LIGHT CONDITION
POWER + TSTAT/CIRC High voltage detected on TSTAT circuit.
POWER + DAMPER Damper stuck closed or unable to close end
switch within 45 seconds from TSTAT call.
POWER + FLAME Flame sensed without call for heat or out
of sequence during ignition trial.
CAUTION Summary (Flashing LED’s)
INDICATOR LIGHT CONDITION
DAMPER Damper end switch opened after it had
been proven closed.
LIMIT Fault detected in temperature sensing
hardware.
FLAME Flame loss or ame not sensed during
trial for ignition.
LWCO LWCO circuit approaching lockout state.
Sensor requires maintenance. LWCO
LED will ash 3 times when maintenance
is required.
Troubleshooting the control module
See Figure 30, page 50, for location of harness plug receptacles and plugs on the
control module.
Part Number 550-142-300/0520
50
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
11b
Troubleshooting — spark-pilot boilers (continued)
Figure 30 Control module connections
Part Number 550-142-300/0520
51
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
11b
Troubleshooting — spark-pilot boilers (continued)
Boiler should now
operate normally.
Problem is with incoming
electricity. Have licensed
electrician repair circuit.
Have system checked by a
licensed electrician.
If problem persists, contact
your Weil-McLain Technical
support.
CHART 1 –– Spark-ignited pilot –– Troubleshooting POWER light status
–– Usually indicates reversed 120 VAC polarity if POWER light ashes 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.
TSTAT/CIRC
light ashing
Chart
2
DAMPER
light ashing
Chart
3
FLAME
light ashing
Chart
4
Chart
6
LWCO
light solid
Chart
7
For insufcient heat or no heat problem, go to
Chart 5, page 56, if POWER light is on steady,
with no other light ashing.
Is POWER light off?
No Yes
• Make sure service switch or circuit breaker is on or
fuses are good.
• Remove 120 VAC IN plug (Figure 30, Item 3,
page 50) on
control module
.
• Using voltmeter, check across black and white wire
pins of 120 VAC IN plug.
Does voltmeter indicate 120 VAC ?
No Yes
• Reconnect 120 VAC IN plug.
• Remove transformer plug (Figure 30, Item 2,
page 50) on
control module
.
• Using voltmeter, check across left side top and
bottom pins of transformer receptacle.
Does voltmeter indicate 120 VAC ?
No Yes
• Reinstall transformer plug.
• Remove TSTAT transformer plug (Figure 30, Item 5,
page 50) on
control module
.
• Using voltmeter, check across left and right pins of
receptacle.
Does voltmeter indicate 120 VAC ?
No Yes
Replace transformer.
Retest.
Replace control module.
Retest.
Replace control module.
Retest.
Is POWER light . . .
Flashing
alone
Flashing with
another light
On steady
(NOT ashing)
• Usually indicates polarity on incoming 120 VAC power
line is wrong or has insufcient earth ground.
• Check grounds to make sure unit has sufcient grounding.
•
▲ 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.
Is POWER light ashing now?
No Yes
Part Number 550-142-300/0520
52
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
11b
Troubleshooting — spark-pilot boilers (continued)
• Boiler should now operate per normal sequence of
operation shown in Figure 24, page 35.
CHART 2 –– 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 nd a voltage across the two external thermostat circuit wires ?
Yes No
• If no voltage is found under any condition on the external
thermostat circuit, connect the two boiler thermostat
connection leads together (or jumper the boiler aquastat
T-T terminals).
• Turn off power to the boiler for 1 minute.
• Turn on power and allow boiler to cycle.
Do the TSTAT and POWER lights still ash ?
No Yes
• Replace control module.
• Retest.
•
Leave external boiler thermostat connection wires
disconnect from boiler.
• Troubleshoot the external thermostat circuit until you nd
the source of the stray voltage. (Pay close attention to
the wiring connections to 3-wire zone valves).
• 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.
Part Number 550-142-300/0520
53
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
11b
Troubleshooting — spark-pilot boilers (continued)
• Make sure thermostat is
calling for heat. If lights
still don’t come on, see
Chart 6, page 56.
CHART 3 –– Spark-ignited pilot –– DAMPER light flashing
–– If POWER light is ashing: Usually indicates vent damper failed to prove open within 45 seconds ––
–– 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 2 to 40 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 5 minutes.
Is Damper light ashing?
No Yes
• Remove damper wiring
plug at damper and rmly
reconnect.
• Recheck boiler operation.
• If problem persists,
replace vent damper
assembly or actuator.
• Wait 45 seconds.
Does vent damper operate ?
No Yes
• Remove Damper plug (Figure 30, Item 6, page 50)
from plug receptacle of control module.
• Place voltmeter leads across the top two pins (1 and 4)
of the Damper receptacle.
Does voltmeter indicate 24 VAC ?
No Yes
Are the TSTAT CIRC and LIMIT lights on steady ?
Yes No
• 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 satised.
Does vent damper actuator
indicator show damper is
open ?
No Yes
• Replace vent damper
assembly or actuator.
• Retest.
• Replace control
module.
• Retest.
Part Number 550-142-300/0520
54
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
11b
Troubleshooting — spark-pilot boilers (continued)
CHART 4 –– Spark-ignited pilot –– FLAME & POWER lights flashing
–– Usually indicates ame sensed when it shouldn’t be there ––
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 manual main shutoff valve and gas valve open ?
No Yes
• 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 (Section 9b) or on boiler label.
• Look through the pilot inspection port to see if the pilot is
burning.
Is pilot burning?
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 (Section 9b) or on boiler label.
Do FLAME and POWER lights still ash ?
No Yes
• Replace gas valve.
• Retest.
Are FLAME and POWER lights ashing?
No Yes
• Replace control module.
• Retest.
• Allow boiler to continue cycling.
Are FLAME and POWER lights ashing?
No Yes
• Replace control
module.
• Retest.
• Boiler may now be
operating
normally.
• Perform start-up
procedures in
boiler manual to
verify proper
operation.
• Replace control
module.
• Retest.
• Boiler should now
operate normally.
• Original ashing
FLAME light
caused by gas
valve not
operating properly.
• See normal
sequence of
operation,
Figure 24,
page 35.
•
▲ 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 550-142-300/0520
55
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
11b
Troubleshooting — spark-pilot boilers (continued)
CHART 5 –– 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.
• Is pilot flame visible through inspection port ?
No Yes
Are main manual shutoff valve and 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
• ▲ TURN OFF POWER ▲
to boiler at service switch or
breaker.
• Remove base access panel
(see Figure 32, item 4,
page 60 for location.
• Contact gas supplier to correct
pressure or gas supply.
• Check the voltage across
main gas valve terminals
of the gas valve.
Is 24 VAC present there?
Yes No
• Make sure ground wire
terminal is securely fastened
to control module mounting
screw.
• 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?
No Yes
• ▲ TURN OFF POWER ▲
to boiler at service switch or breaker.
• Check flame signal – Detach sense lead from ignition control
(Figure 30, Item 8, page 50)
.
• Connect negative lead of MICROAMMETER to control sense
terminal
(Figure 30, Item 8, page 50)
. Connect positive
lead of MICROAMMETER to sense wire.
• DISCONNECT red wire connected to main 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
• Check the voltage across
main gas valve terminals
of the gas valve.
Is 24 VAC present there?
No Yes
• If the wiring from the
control module to gas valve
is intact, replace the control
module.
• Retest.
• 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
• Boiler should be in
normal operating
sequence.
• Observe operation
until thermostat is
satisfied and vent
damper has closed.
• Verify pilot gas line is not
kinked, obstructed or dam-
aged 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 wir
-
ing is damaged.
• Reinstall base access panel to
operate boiler for retest after
any changes or corrections.
• If none of the above corrects
problems, then replace the
control module, reinstall base
access panel, and retest.
• ▲ TURN OFF POWER ▲
to boiler at service switch or
breaker.
• Remove base access panel
(see Figure 32, item 4,
page 60 for location.
• Verify pilot burner is securely at-
tached to pilot bracket, bracket
is securely attached to cross-tie,
and there is no corrosion on 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 wir-
ing is damaged.
• 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 550-142-300/0520
56
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
11b
Troubleshooting — spark-pilot boilers (continued)
CHART 6 –– 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 Yes
Is boiler System circulator operating?
No Yes
• Wait 5 minutes.
Is FLAME light on?
Yes No
Is LIMIT light on?
No Yes
Are all red lights off?
No Yes
• Wait 30 seconds.
Are all red lights off?
No Yes
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 temperature
sensor for correct
resistance.
Are resistance values
correct?
No Yes
• Replace control
module.
• Retest.
• Replace control
module.
• Retest.
• Repair/replace
circulator. Retest.
• Repair/replace
wiring. Retest.
• Check any other
limit controls wired
into the limit
circuit. If all are
OK, then replace
control module.
• Retest.
• Correct conditions and
recheck operation.
• See Figure 24, page 35
for normal sequence of
operation.
• Boiler is in standby.
• Set thermostat to call for
heat and recheck operation.
• Verify Sequence of
operation, Figure 24,
page 35.
• Remove CIRCULATOR harness plug from
CIRCULATOR plug receptacle (Figure 30,
Item 7, page 50). Check with voltmeter across
pins of control module receptacle.
Does voltmeter show 120 VAC across pins?
No 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 35.
• If you have less than sufficient heat –
Is vent or combustion air piping free of blockage?
No Yes
Contact your Weil-McLain
Technical support.
• Replace temperature
sensor.
• Retest.
Part Number 550-142-300/0520
57
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
CHART 7 –– Troubleshooting LWCO and POWER light Solid
and/or “LCO” shown on display
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.
11b
Troubleshooting — spark-pilot boilers (continued)
• System is losing water.
• Repair leak and retest.
Is boiler pressurized?
Yes No
• System was low on water.
• Check system ll piping for
leaks or damage.
• Pressurize boiler to system design pressure.
Are lights still solid?
No Yes
• Check system for leaks.
Is system leaking or not
maintaining pressure?
No Yes
• LWCO sensor is bad or fouled.
• Clean LWCO sensor
•
Retest.
Are lights still solid?
No Yes
• Sensor is bad. Replace sensor.
• Retest.
• Sensor was fouled.
• Check water quality and
maintenance schedule.
Part Number 550-142-300/0520
58
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Replacement parts
12a
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 manufac-
tured 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 66 of this manual.
Failure to comply could result in severe personal injury.
Section assembly .............................................. 59
Base .................................................................. 60
Jacket ............................................................... 61
Trim ................................................................... 62
Controls ............................................................ 63
Part Number 550-142-300/0520
59
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Item
number
Description Part number
1
End section, left hand, 51124 311-103-851
2
End section, right hand 51128 311-103-821
3
Intermediate section, 51127 311-103-845
not shown
Replacement
section
assembly
CGa-25 and CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
321-114-360
321-114-361
321-114-362
321-114-363
321-114-364
321-114-365
not shown
Section replacement kit, includes seals and
sealant for 1 joint
381-354-527
4
Tie rod, 7/16”
without nut
(3 per boiler):
CGa-25 & CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
560-234-500
560-234-501
560-234-502
560-234-503
560-234-504
560-234-505
5
Nut, 7/16” (2 per tie rod) 561-928-235
6
Washer,
7/16”
(1 per tie rod) 562-248-684
7
Radiation plate CGa 25 & 3
460-003-018
(1 per joint) CGa 4-8
460-003-017
8
Collector hood
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
381-354-625
381-354-626
381-354-627
381-354-628
381-354-926
381-354-630
381-354-631
Item
number
Description Part number
9 Temperature/LWCO sensor 511-724-305
10 Draft hood
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
450-021-240
450-021-241
450-021-242
450-021-243
450-021-244
450-021-245
450-021-246
11
Spill switch (210°F)
CGa-25 - 8
510-300-013
12 Vent Damper
CGa-25 & 3 4”
CGa-4 5”
CGa-5 & 6 6”
CGa-7 & 8 7”
381-800-474
381-800-475
381-800-476
381-800-477
13 Vent Damper Actuator 510-512-337
14 Vent Damper Harness 591-391-795
Figure 31 Section assembly, flue collector, draft hood and vent damper
Replacement parts — section assembly12b
Part Number 550-142-300/0520
60
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Item
number
Description Part number
Base assembly kit
(includes base panels
items 1, 2, 3, 4, 5, 6 and 7,
plus insulation, air box gaskets,
and hardware))
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
381-354-362
381-354-356
381-354-357
381-354-358
381-354-359
381-354-360
381-354-361
1 Base side panel (in Base assembly)
2 Base front cross-tie assembly (in Base assembly)
3 Base back cross-tie assembly (in Base assembly)
4 Access panel (in Base assembly)
5 Base pan angle, left side (in Base assembly)
6 Base pan angle, right side (in Base assembly)
7 Base pan (in Base assembly)
8 Burner rest CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
450-003-742
450-003-736
450-003-737
450-003-738
450-003-739
450-003-740
450-003-741
9 Base insulation kit
(included insulation for all base
parts above plus gasket material
needed between block assembly
and base)
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
381-354-518
381-354-518
381-354-518
381-354-518
381-354-519
381-354-519
381-354-519
10 Boiler leg kit 590-424-253
11 Manifold CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
591-126-615
591-126-616
591-126-617
591-126-618
591-126-619
591-126-556
591-126-557
12 Main burner orice – Natural gas, sea level
Main burner orice – Natural gas, sea level
560-528-997
560-528-998
13 Burner, stainless steel 512-200-077
14 Burner with pilot 512-200-078
15 Screw, 10-32 x
.
0.38 STP type D hex, washer
head slot
available at
local supply
house
16 Rollout thermal fuse element 512-050-230
Replacement parts — base
12c
Figure 32 Base assembly, manifold, orifices and burners
Part Number 550-142-300/0520
61
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Replacement parts — jacket
12d
Boiler
Model
1 2 3 4 5
Boiler
Model
Junction box, 2 x 4 Jacket panel, left side, with insulation Jacket panel,
right side,
with insulation
Jacket panel,
top front
Jacket panel,
top rear
Natural Gas
Spark Pilot
Propane Gas
Spark Pilot
Part numbers
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
(Available at local
supply house)
381-359-201
381-359-202
381-359-203
381-359-204
381-359-205
381-359-206
381-359-207
381-359-208
381-359-209
381-359-210
381-359-211
381-359-212
381-359-213
381-359-214
381-359-229
381-359-229
381-359-229
381-359-229
381-359-229
381-359-229
381-359-229
381-359-230
381-359-230
381-359-231
381-359-232
381-359-233
381-359-234
381-359-235
381-359-236
381-359-236
381-359-237
381-359-238
381-359-239
381-359-240
381-359-241
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
Boiler
Model
6 7 8 9 10
Boiler
Model
Jacket panel,
door
Jacket cross tie,
bottom front
Jacket panel,
interior,
with insulation
Jacket panel,
rear,
with insulation
Not shown —
touch-up paint
Part numbers
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
381-359-248
381-359-248
381-359-249
381-359-250
381-359-251
381-35-9252
381-359-253
381-359-260
381-359-260
381-359-261
381-359-262
381-359-263
381-359-264
381-359-265
381-359-266
381-359-266
381-359-267
381-359-268
381-359-269
381-359-270
381-359-271
381-359-272
381-359-272
381-359-273
381-359-274
381-359-275
381-359-276
381-359-277
381-359-278 Cloud
384-000-141 Slate
CGa-25
CGa-3
CGa-4
CGa-5
CGa-6
CGa-7
CGa-8
Figure 33 Jacket assembly
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Replacement parts — trim
12e
Figure 34 Trim assembly
Item
number
Description
Part number
1 Pressure relief valve, ASME, 30 PSIG, ¾” male inlet
Pressure relief valve, ASME, 30 PSIG, ¾” female inlet
(Fittings shown are factory-installed on boiler.)
511-546-920
511-546-924
2 Combination pressure-temperature gauge, 3⅛,” diameter, short shank
(Fittings shown are shipped loose with boiler.)
380-000-000
3 Drain valve, ¾”
(Fittings shown are included with boiler.)
511-210-423
4 Circulator
(Fittings shown are shipped loose with boiler.)
CGa 25 - 5
CGa 6 - 8
511-405-153
511-405-113
5 Circulator gasket, universal (2 per boiler) 590-317-535
not shown
Circulator hardware kit, includes:
1 ange, 2 nuts, 2 screws, 1 gasket —
¾” NPT — CGa-25 --------------------------------------------
1” NPT — CGa-3 through CGa-5 -------------------------
1¼” NPT — CGa-6 and CGa-7 ----------------------------
1½” NPT — CGa-8 -------------------------------------------
381-354-530
381-354-525
381-354-526
381-354-531
6 Circulator wiring harness kit, spark-ignited with Molex (loose) 381-356-528
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Replacement parts — controls
12f
Figure 35 Gas control components
Item
number
Description Boiler model Part number
Natural gas components
1 Gas Valve, ½” x ½”
Gas valve,
¾” x ¾”
CGa-25 through CGa-6
CGa-7 & CGa-8
511-044-381
511-044-382
2 Pilot kit w/orice & aluminum pilot gas tubing 511-330-218
Liqueed Petroleum (Propane) gas components
1
Gas Valve,
¾” x ¾”
Gas Valve,
¾” x ¾”
CGa-25 through CGa-7
CGa-8
511-044-356
511-044-366
2 Pilot kit w/orice & aluminum pilot gas tubing 511-330-273
Natural gas and Liqueed Petroleum (Propane) gas components
3 Control Module - Natural gas
- Liqueed Petroleum (Propane) gas
381-330-039
381-330-038
not shown Wiring Harness, Junction box to Control Module 591-391-975
not shown Wiring Harness, Controls to Control Module 591-391-977
not shown Wiring Harness, Thermostat 591-392-006
not shown Wiring Harness, Water Temperature/LWCO Sensor 591-391-995
4 Control Transformer 381-356-578
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Dimensions13a
Figure 36 Dimensional drawing — ALL DIMENSIONS IN INCHES
Boiler
model
number
Supply
tapping
(inches NPT)
Return
tapping
(inches NPT)
Gas connection
& manifold size
Note 3
(inches NPT)
“A”
Vent
location
(inches)
“D”
Vent
diameter
(inches)
“W”
Jacket
width
(inches)
“H”
Damper
height
(inches)
CGa-25 1 ¼ 1 ¼ ½ 5 4 10 45-
3/8
CGa-3 1 ¼ 1 ¼ ½ 5 4 10 52-
3/8
CGa-4 1 ¼ 1 ¼ ½ 6-½ 5 13 54-
3/8
CGa-5 1 ¼ 1 ¼ ½ 8 6 16 57-
7/8
CGa-6 1 ¼ 1 ¼ ½ 9-½ 6 19 60-
7/8
CGa-7 1 ¼ 1 ¼ ¾ 11 7 22 62-
1/8
CGa-8 1 ¼ 1 ¼ ¾ 12-½ 7 25 64-
7/8
Note 3:
Gas piping from meter to boiler to be sized per local utility requirements.
AHRI Certied Ratings
Boiler
model
number
0 - 2,000 feet
Altitude
2,000 - 4,500 feet
Altitude
Heating
Capacity
Seasonal
Efciency
PIDN-PIDL
Net
Ratings
Boiler
water
content
Chimney
and
breeching
size
(Note 1)
Input
(Btuh)
Output
(Btuh)
Input
(Btuh)
Output
(Btuh)
Btuh
(Note 2)
AFUE %
Btuh
(Note 3)
(gallons)
Inches
CGa-25 38,000 32,000 34,000 29,000 32,000 84.0 27,000 1.5 4"I.D. x 20’
CGa-3 67,000 56,000 60,000 50,000 56,000 84.0 48,000 1.5 4”I.D. x 20’
CGa-4 100,000 84,000 90,000 76,000 85,000 84.0 73,000 2.1 5”I.D. x 20’
CGa-5 133,000 112,000 120,000 101,000 113,000 84.0 98,000 2.7 6”I.D. x 20’
CGa-6 166,000 139,000 149,000 125,000 141,000 84.0 122,000 3.3 6”I.D. x 20’
CGa-7 200,000 168,000 180,000 151,000 170,000 84.0 147,000 3.8 7”I.D. x 20’
CGa-8 233,000 196,000 210,000 176,000 198,000 84.0 172,000 4.4 7”I.D. x 20’
Notes
1. Add “PIN” for natural gas boiler - “PIL” for Liqueed Petroleum (propane) gas boiler.
2. Based on standard test procedures prescribed by the United States Department of Energy.
3. Net AHRI ratings are based on net installed radiation of sufcient 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.
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Ratings13b
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.
Table 8 Ignition system model suffixes
Pilot ignition system Natural gas Propane gas
Spark-ignite pilot PIDN PIDL
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Handling ceramic fiber and fiberglass materials
REMOVAL OF COMBUSTION CHAMBER
LINING OR BASE PANELS
The combustion chamber lining or base
insulation panels in this product con-
tain ceramic fiber materials. Ceramic
fibers can be converted to cristobalite in
very high temperature applications. The
International Agency for Research on
Cancer (IARC) has concluded, “Crystal-
line silica inhaled in the form of quartz
or cristobalite from occupational sources
is carcinogenic to humans (Group 1).”:
Precautionary measures
❏ Avoid breathing fiberglass dust and contact with skin or
eyes.
• Use NIOSH certified dust respirator (N95).
This type of respirator is based on the
OSHA requirements for fiberglass wool at the
time this document was written. Other types of
respirators may be needed depending on the
job site conditions. Current NIOSH recommen-
dations can be found on the NIOSH web site
at http://www.cdc.gov/niosh/homepage.html.
NIOSH approved respirators, manufacturers, and
phone numbers are also listed on this web site.
• Wear long-sleeved, loose fitting clothing, gloves,
and eye protection.
❏ Apply enough water to the combustion chamber lining
or base insulation to prevent airborne dust.
❏ Remove combustion chamber lining or base insulation
from the boiler and place it in a plastic bag for disposal.
❏ Wash potentially contaminated clothes separately from
other clothing. Rinse clothes washer thoroughly.
NIOSH stated First Aid.
❏ Eye: Irrigate immediately.
❏ Breathing: Fresh air.
REMOVAL OF FIBERGLASS WOOL
or
INSTALLATION OF FIBERGLASS WOOL,
COMBUSTION CHAMBER LINING OR
BASE PANELS:
This product contains fiberglass jacket
insulation and ceramic fiber materi-
als in combustion chamber lining or
base panels in gas fired products. Air-
borne fibers from these materials have
been listed by the State of California
as a possible cause of cancer through
inhalation.
Precautionary measures
❏ Avoid breathing fiberglass dust and contact with skin
or eyes.
• Use NIOSH certified dust respirator (N95).
This type of respirator is based on the
OSHA requirements for fiberglass wool at the
time this document was written. Other types of
respirators may be needed depending on the
job site conditions. Current NIOSH recommen-
dations can be found on the NIOSH web site
at http://www.cdc.gov/niosh/homepage.html.
NIOSH approved respirators, manufacturers,
and phone numbers are also listed on this web
site.
• Wear long-sleeved, loose fitting clothing, gloves,
and eye protection.
❏ Operations such as sawing, blowing, tear out, and
spraying may generate airborne fiber concentration
requiring additional protection.
❏ Wash potentially contaminated clothes separately
from other clothing. Rinse clothes washer thoroughly.
NIOSH stated First Aid.
❏ Eye: Irrigate immediately.
❏ Breathing: Fresh air.
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CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Notes
68
CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
Part Number 550-142-300/0520
