Weil-McLain GV90+ Guide

Part number 550-142-055/0411
®
Gas-Fired Water Boilers
User’s
Information Manual
If the information in this manual is not followed exactly, a fire or explosion may result,
causing property damage, personal injury or loss of life.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
— WHAT TO DO IF YOU SMELL GAS —
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any telephone in your building.
• Immediately call your gas supplier from a neighbor’s telephone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
Installation & service must be performed by a qualified installer, service technician or the gas supplier.

Part number 550-142-055/0411
GV90+ gas-fired water boiler — User’s Information Manual
2
Please read this page first
How to use this
manual . . . To . . . Read/use . . . Page . . .
Learn
precautions Warnings and definitions 3
Prevent air
contamination
Laundry room or pool — make sure boiler air is
piped to boiler per manual.
Read list of air contaminants you must avoid. Have
boiler air piped in if you can’t avoid.
4
Maintain
boiler
Set up a plan for maintaining the boiler using
the schedule included in this manual.
Schedule an annual start-up by a qualified
service technician before every heating season.
5
Locate boiler
components How the boiler works and illustration. 10
Start — or —
Shutdown
boiler
Follow the Lighting instruction sheet details to
start or shutdown your boiler. 12
Troubleshoot
common
problems
Use the common problems/solutions table to
resolve typical heating system/boiler problems. 13

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STOP!! — Read before proceeding
Failure to adhere to the guidelines on this page can result
in severe personal injury, death or substantial property
damage.
Boiler service and maintenance —
• To avoid electric shock, disconnect electrical supply before
performing maintenance.
• To avoid severe burns, allow boiler to cool before performing
maintenance.
• You must maintain the boiler as outlined in the manual and have
the boiler started up and serviced at least annually by a
qualified service technician to ensure boiler/system reliability.
Boiler operation —
• Do not block flow of combustion or ventilation air to boiler. This
boiler is equipped with a control which will automatically shut down
the boiler should air or vent be blocked. If vent or air blockage is
easily accessible and removable, remove it. The boiler should attempt
to restart within an hour. If blockage is not obvious or cannot be
removed, have the boiler and system checked by a qualified service
technician.
• Should overheating occur or gas supply fail to shut off, DO NOT
turn off or disconnect electrical supply to circulator. Instead, shut off
the gas supply at a location external to the appliance.
• Do not use this boiler if any part has been under water. Imme-
diately call a qualified service technician to inspect the boiler and to
replace any part of the control system and any gas control that has
been under water.
Combustion air —
• DO NOT install combustion air intake where there is a risk of
combustion air contamination.
Carbon monoxide detector —
• For Direct Exhaust units, a carbon monoxide detector is required
in the boiler room. The carbon monoxide detector must be wired
on the same electrical circuit as the boiler.
• For Direct Vent units, a carbon monoxide detector that is wired on
the same electrical circuit as the boiler is strongly recommended.
Boiler water —
• Do not use petroleum-based cleaning or sealing compounds in boiler
system. Gaskets and seals in the system may be damaged. This can
result in substantial property damage.
• Leaks in boiler or piping must be repaired at once to prevent
make-up water. Use this boiler ONLY in a closed-loop system.
Continual fresh make-up water will reduce boiler life. Mineral build-
up in heat exchangers reduces heat transfer, overheats the materials,
and causes failure. Addition of oxygen carried in by make-up water
can cause internal corrosion.
• Do not add cold water to hot boiler. Thermal shock can cause heat
exchanger 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 replacement boiler system that has used glycol before installing
the new boiler.
User — Have this boiler serviced/
inspected by a qualified service tech-
nician, at least annually.
Failure to comply with the above
could result in severe personal injury,
death or substantial property dam-
age.
When calling or writing about the
boiler— Please have the boiler
model number from the boiler rat-
ing label and the CP number from
the boiler jacket.
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 dam-
age.
Indicates presence of hazards that
can cause severe personal injury,
death or substantial property dam-
age.
Indicates presence of hazards that
will or can cause minor personal
injury or property damage.
Indicates special instructions on in-
stallation, operation or maintenance
that are important but not related to
personal injury or property damage.

Part number 550-142-055/0411
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Air contamination
Common household and hobby products often contain
fluorine or chlorine compounds. When these chemicals
pass through the boiler, they can form strong acids in
the vent system or boiler. The acid can eat through
the vent or boiler wall, causing serious damage and
presenting a possible threat of flue gas spillage into
the building.
Please read the information below. If the contaminating
chemicals will be present, have your installer pipe the
boiler air from outside per the Boiler manual.
If the boiler is installed in any area
likely to cause contamination, or if
products which would contaminate the
air cannot be removed, you must pipe
combustion air to the boiler air in-
take. Contaminated combustion air will
damage the boiler and vent system, re-
sulting in possible severe personal injury,
death or substantial property damage.
Do not operate a GV90+ boiler in
a laundry room or pool facility, for
example, without using ducted outside
air. These areas will always contain con-
taminants.
Prevent combustion air contamination —
Combustion air contamination:
Ensure that the combustion air will not contain any of
the contaminants in Figure 1.
Combustion air supply openings or intake terminations
must NOT be near a swimming pool, for example.
Avoid areas subject to exhaust fumes from laundry facilities.
These areas will always contain contaminants.
Figure 1 Corrosive contaminants and sources
Products to avoid
Spray cans containing chloro/fluorocarbons
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
Excessive dust and dirt
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 refinishing areas and establishments
New building construction

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GV90+ gas-fired water boiler — User’s Information Manual
Perform maintenance per schedule below
Figure 2 Service and maintenance schedules
Service technician
(see Boiler Manual for instructions)
Owner maintenance
(see following pages for instructions)
Annnual start-up
Follow the procedures listed in
the Boiler Manual.
Daily
• Check boiler area
• Check air openings
• Check pressure gauge
Monthly
• Check boiler interior piping
• Check venting system
• Check air vents
• Check condensate drain system
• Check relief valve
Periodically
• Test low water cutoff (if used)
• Clean vent termination/air intake
screens
Every 6 months • Oil blower motor
• Operate relief valve
End of season • Shut down procedure

Part number 550-142-055/0411
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DAILY
Maintenance
Boiler must
be serviced
and
maintained
Check boiler area
To prevent potential of severe personal injury, death or substantial property
damage, eliminate all materials discussed below from the boiler vicinity. If con-
taminants are found:
Remove products immediately from the area. If they have been there for an ex-
tended period, call a qualified service technician to inspect the boiler and vent
system for possible damage from acid corrosion.
If products cannot be removed, immediately call a qualified service technician to
install an outside combustion air source for the boiler (if not already installed).
1. Combustible/flammable materials — Do not store combustible materials, gasoline or any
other flammable vapors or liquids near the boiler. Remove immediately if found.
2. Air contaminants — Products containing chlorine or fluorine, if allowed to contaminate
the boiler intake air, will cause acidic condensate in the vent and boiler. This will cause
significant damage to the vent and/or boiler if allowed to continue. Read the list of potential
materials listed on page 4 of this manual. If any of these products are in the room from
which the boiler takes its combustion air, they must be removed immediately or the boiler
combustion air must be supplied from outside. See WARNING above.
Check air openings
1. Verify that combustion and ventilation air openings to the boiler room and/or building
are open and unobstructed.
2. Verify that boiler vent discharge and air intake are clean and free of obstructions. Remove
any debris on the air intake or flue exhaust openings.
Check boiler pressure/temperature gauge
1. Make sure the pressure reading on the boiler pressure/temperature gauge does not exceed
24 psig. Higher pressure may indicate a problem with the expansion tank.
2. Contact a qualified service technician if problem persists.
User maintenance procedures
The boiler should be inspected and started annually, at the beginning of the heat-
ing season, only by a qualified service technician. In addition, the maintenance
and care of the boiler designated on page 5 and explained on the following pages
must be performed to assure maximum boiler efficiency and reliability. Failure
to service and maintain the boiler and system could result in equipment failure,
causing possible severe personal injury, death or substantial property damage.
The following information provides detailed instructions for completing the
maintenance items listed in the maintenance schedule, page 5. In addition to
this maintenance, the boiler must be serviced and started up at the beginning of
each heating season by a qualified service technician.

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MONTHLY
Maintenance
Check boiler interior piping
1. Remove boiler jacket top.
2. Visually inspect for leaks around internal piping, circulators, relief valve and other fittings.
Immediately call a qualified service technician to repair any leaks.
Have leaks fixed at once by a qualifed service technician. Continual fresh makeup
water will reduce boiler life. Minerals can build up in sections, reducing heat
transfer, overheating cast iron, and causing section failure.
Do not use petroleum-based cleaning or sealing compounds in boiler
system. Severe damage to boiler and system components can occur, resulting in
possible severe personal injury, death or substantial property damage.
User maintenance procedures (continued)
Check venting system
1. Visually inspect the flue gas vent piping for any signs of blockage, leakage or deterioration
of the piping. Notify your qualified service technician at once if you find any problem.
Failure to inspect the vent system as noted above and have them repaired by a
qualifed service technician can result in vent system failure, causing severe per-
sonal injury or death.
Check automatic air vents (if used — use automatic air
vents with diaghragm-type expansion tanks only)
1. See Figure 3.
2. Remove the cap from any automatic air vent in the system and check operation by depress-
ing valve “B” slightly with the tip of a screwdriver.
3. If the air vent valve appears to be working freely and not leaking, replace cap “A”, twisting
all the way on.
4. Loosen cap “A” one turn to allow vent to operate.
5. Have vent replaced if it does not operate correctly.
Figure 3 Automatic air vent

Part number 550-142-055/0411
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Check condensate system
1. NOTICE — To improve clarity, this
illustration of the condensate trap is
shown with no air inlet pipe attached.
If your boiler has an air pipe connected
here, DO NOT tamper with it. The trap
is also shown as item m on page 11.
2. Inspect the condensate P-trap (item 1
in the illustration at right). The trap is
translucent. You should be able to see
water in the trap as shown.
3. If the trap does not contain water, turn
off the boiler ON/OFF switch and call
your boiler service technician imme-
diately.
4. Item 2 in the illustration is the tubing or
pipe from the boiler condensate outlet to the condensate drain or condensate pump. Inspect
this tubing or piping, making sure it is in good condition and not obstructed.
If the condensate trap is dry or the condensate line is damaged or obstructed,
there is a risk of flue gas flow into the building. The boiler must not be operated
and must be inspected and serviced only by a qualified service technician. Failure
to comply with this directive could result in the possibility of severe personal
injury, death or substantial property damage.
Check boiler relief valve
1. Inspect the boiler relief valve and the relief valve discharge pipe for signs of weeping or
leakage.
2. If the relief valve often weeps, the expansion tank may not be working properly. Immediately
contact your qualified service technician to inspect the boiler and system.
Test low water cutoff (if installed)
1. If the system is equipped with a low water cutoff, test the low water cutoff periodically
during the heating season, following the low water cutoff manufacturer’s instructions.
Clean vent termination & air intake screens
1. Remove all lint and debris from both the boiler air intake screen and the flue discharge
screen.
2. The boiler control module will sense blockage of the air intake or flue and lockout if the
blockage is excessive. It will signal the failure by flashing the appropriate indicator lights
on the control board.
3. If removing the debris does not allow the boiler to operate correctly afterwards, contact
your qualifed service technician to inspect the boiler and vent/air systems.
User maintenance procedures (continued)
MONTHLY
Maintenance
PERIODIC
Maintenance

Part number 550-142-055/0411 9
GV90+ gas-fired water boiler — User’s Information Manual
Operate boiler relief valve
1. Before proceeding, verify that the relief valve outlet has been piped to a safe place of dis-
charge, avoiding any possibility of scalding from hot water.
To avoid water damage or scalding due to valve operation, a metal discharge line
must be connected to relief valve outlet and run to a safe place of disposal. This
discharge line must be installed by a qualifed heating installer or service techni-
cian in accordance with the instructions in the GV90+ Boiler Manual. The
discharge line must be terminated so as to eliminate possibility of severe burns
should the valve discharge.
2. Read the boiler pressure/temperature gauge to make sure the system is pressurized.
3. Lift the relief valve top lever slightly, allowing water to relieve through the valve and dis-
charge piping.
4. If water flows freely, release the lever and allow the valve to seat. Watch the end of the relief
valve discharge pipe to ensure that the valve does not weep after the line has had time to
drain. If the valve weeps, lift the seat again to attempt to clean the valve seat. If the valve
continues to weep afterwards, contact your qualified service technician to inspect the valve
and system.
5. If water does not flow from the valve when you lift the lever completely, the valve or discharge
line may be blocked. Immediately shutdown the boiler, following the lighting instructions
on the inside jacket top. Call your qualified service technician to inspect the boiler and
system.
Follow boiler shutdown procedure
1. Follow “TO TURN OFF GAS TO APPLIANCE” on the Operating instruction on the
inside of the jacket top panel. You will also find these instructions on page 12 of this manual.
2. Do not drain system unless exposure to freezing temperatures will occur.
3. Do not drain the system if it is filled with an antifreeze solution.
4. Do not shut down boilers used for domestic water heating. They must operate year-round.
Oil blower motor
1. Remove the jacket top panel to access the blower
motor.
2. Use only Anderol 465. DO NOT use household
universal oils.
Use only Anderol 465 to lubricate the
blower motor. Do not use common uni-
versal household oils.
3. See Figure 4
4. Place a few drops of oil in each of the two oiler cups
on the side of the blower motor.
Figure 4 Blower motor
User maintenance procedures (continued)
EVERY
6 MONTHS
Maintenance
END OF
SEASON
Maintenance

Part number 550-142-055/0411
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1 Integrated boiler control
The integrated boiler control (IBC) responds to signals from the room thermostat, air
pressure switch, inlet water sensor and boiler limit circuit to operate the circulators,
gas valve, igniter and blower. When a room thermostat calls for heat, the IBC starts the
system circulator and blower.
The IBC runs the blower to purge the boiler flue passages, then turns on the igniter and
lets it warm up.
After igniter warm-up, the IBC opens the gas valve, turns the igniter off, and checks for
flame. The flame must come on within 4 seconds or the IBC will shut down and try the
full cycle again.
When the room thermostat is satisfied, the IBC turns off the boiler components and
waits for the next heat call.
The IBC indicator lights show normal sequence when the lights are on steady. When a
problem occurs, the IBC flashes combinations of lights which indicate the most likely
reason for the problem.
2 Transformer
The control transformer reduces line voltage to 24 volts for the gas valve and limit circuit.
3 Blower
The blower pulls in air and mixes it with gas from the gas valve. The blower forces this
mixture into the burner for combustion inside the boiler chamber.
4 Recuperator
The recuperator is a stainless steel heat exchanger that increases boiler efficiency by ex-
tracting additional heat from the flue gases. Return water passes through the recuperator
before entering the boiler.
5 Water temperature limit switch
The water temperature limit switch turns off the gas valve if the temperature in the
boiler goes above its setting. (The circulators will continue to run as long as there is a
call for heat.)
6 System circulator
The system circulator circulates water through the external (system) piping. The flow
rate of the circulator is controlled by the IBC, depending on the temperature of the water
entering the boiler sections. Pump must remain on boiler — do not remove.
7 Bypass circulator
The IBC operates the bypass circulator to mix hot water from the boiler outlet with
colder return water from the system as needed to prevent condensation of flue gases in
the cast iron heat exchanger.
When the water returning to the boiler is below 140°F, the IBC regulates the bypass
circulator and system circulator flow rates to raise the return water temperature up to
140°F before it enters the cast iron sections. By balancing these flow rates, the IBC can
protect against condensation even if return water is as low as 60°F.
Pump must remain on boiler — do not remove.
8 Air pressure switch
The air pressure switch signals the IBC, telling the control whether air is moving through
the blower.
9 Water temperature sensor
The water temperature sensor monitors the temperature of the water entering the boiler
sections. The sensor sends this information to the IBC. The IBC determines how much
to adjust the circulator flow rates to provide at least 140°F water to the cast iron heat
exchanger.
How it works . . .
LEGEND
a Supply to system, 1” NPT
b Return from system, 1” NPT
c Combustion air inlet fitting —
3” PVC connection
d Flue outlet — 3” PVC connection
e Gas valve — negative pressure
regulated gas control
f Pressure/temperature gauge
g Flueway inspection port cover
h Sensor hose trap
i Manual air vent
j Relief valve
k Thermal fuse — a one-time fuse
device that shuts boiler off if flue
temperature exceeds its setpoint
m Condensate trap line — shipped
loose with boiler, field installed
n Condensate drain connection —
½” PVC female
This boiler uses a negative-pressure-
regulated gas valve, set for an outlet
pressure approximately –0.20” water
column.
DO NOT set the outlet pressure higher
than factory setting.