A.O. Smith FPSE-75 Owner's Manual page 17

WARNING: DO NOT BY-PASS ANY CONTROLS TO MAKE HEATER OPERATE. OPERATE ONLY AS WIRED FROM FACTORY.
For your safety, water heater service should be performed only by a qualified service technician.
PROBLEM
1) Blower will not run
2) Blower running, burner not on
NOT ENOUGH OR
NO HOT WATER
3) Thermostat problems
4) Others
VENT PIPE TOO HOT
(ABOVE 170° F)
YELLOW FLAME
CONDENSATION
Improperly sealed, hot or cold supply connections,
relief valve, drain valve or thermostat threads
WATER LEAKS
Leakage from other appliances or water lines
Condensation of flue products
Thermal expansion in closed water system
LEAKING T&P VALVE
Improperly seated valve
High sulfate or mineral content in water supply or
HOT WATER ODORS OR COLOR
iron or sulfate reducing bacteria in water supply
(Refer to CATHODIC PROTECTION)
TROUBLESHOOTING
Read the GENERAL SAFETY INFORMATION section first.
POSSIBLE MALFUNCTION
A ) "ON/OFF" control switch turned off
B) Blower unplugged
C) No power at outlet
D) "ON/OFF" switch defective
E) Control harness defective
F) Blower motor defective
A ) Fan not running fast enough to close
air switch contacts
B) Air pressure switch defective
C) Gas valve defective
D) Control harness defective
E) Igniter defective
F) Unit has completed three trials to light
and failed
G) Discharge air limit tripped
A ) Thermostat set too low
B) Thermostat or ECO defective
C) High limit control circuit open
A ) Heater undersized
B) Low gas pressure
C) Incoming water is unusually cold
D) Leaking hot water pipes or fixtures
A ) Blower does not run when heater fired
B) Not enough dilution air to mix with flue
gases in "Tee"
C) Air in room too hot for mixing with flue gases
D) Wrong burner orifice
A ) Dirt in burner ports
B) Combustion air path restricted
C) Not enough room air for proper combustion
A ) Water on the floor under heater
B) Water dripping from fan
SERVICE TO BE PERFORMED
Turn switch to the "ON" position.
Plug blower back into 115 vac. outlet.
Repair service to outlet.
Replace switch.
Replace control harness.
Replace blower and motor.
Replace switch.
Check for low voltage, less than 102 vac., have service
checked and repaired.
If voltage is above 102 vac., make sure there is not more than
30 Equivalent feet of 3 inch pipe or 60 equivalent feet of 4 inch
pipe installed or vent terminal blockage.
If at least 102 vac., less than 30 equivalent feet of 3 inch pipe
or 60 equivalent feet of 4 inch pipe and not terminal blockage,
replace blower.
Replace switch.
Replace gas valve.
Replace harness.
Replace igniter.
Reset cycle by turning switch off and then back on. If unit
does not light in three trials, call an authorized A.O. Smith
service representative.
Verify dilution air openings are free of obstructions.
Make sure there is no more than 30 equivalent feet of 3 inch pipe or
60 equivalent feet of 4 inch pipe.
Check for low voltage, less than 102 vac., have service
checked and repaired.
Make sure vent terminal is not blocked.
Turn temperature control higher.
Replace thermostat.
Replace.
Reduce hot water use.
Contact an authorized A.O. Smith service representative.
Allow more time for heater to re-heat.
Have plumber check and repair leaks.
Take unit out of service immediately, call an authorized A.O.
Smith service representative.
Proper air circulation must be provided for combustion and
dilution of flue temp. Refer to "INSTALLATION" section.
Room air to be used for dilution with combustion products in
flue should be less than 90°F.
Install correct orifice.
Turn off heater and gas, clean burner head.
Clear area around heater and check under heater, remove
any debris under heater and in openings in bottom cover.
Refer to installation manual - Confined and Unconfined Space
statements on page 4 and 5 for required openings.
See "CONDENSATION."
Provide drip "TEE" to catch condensation, refer to pages 8 and 10.
Turn off heater & water, repair unit.
Inspect other appliances near water heater.
Refer to "CONDENSATION."
Install thermal expansion tank (DO NOT plug T&P valve).
Check relief valve for proper operation (DO NOT plug T&P valve).
Drain and flush heater thoroughly, chlorinate, refill and flush
again then chlorinate water supply.
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