A.O. Smith FPSH - 75 owner manual Troubleshooting

WARNING: DO NOT BY-PASSANY CONTROLS TO MAKE HEATER OPERATE. OPERATE ONLYAS WIRED FROM FACTORY.

TROUBLESHOOTING

For your safety, water heater service should be performed only by a qualified service technician.

Read the GENERAL SAFETY INFORMATION section first.

PROBLEM			POSSIBLE MALFUNCTION	SERVICE TO BE PERFORMED
	1)	Blower will not run
		A)	“ON/OFF” control switch turned off	Turn switch to the “ON” position.
		B)	Blower unplugged	Plug blower back into 115 vac. outlet.
		C)	No power at outlet	Repair service to outlet.
		D)	“ON/OFF” switch defective	Replace switch.
		E)	Control harness defective	Replace control harness.
		F)	Blower motor defective	Replace blower and motor.
	2)	Blower running, burner not on		Replace switch.
		A)	Fan not running fast enough to close	Check for low voltage, less than 102 vac., have service
			air switch contacts	checked and repaired.
				If voltage is above 102 vac., make sure there is not more than
				30 Equivalent feet of 3 inch pipe or85 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 85 equivalent feet of 4 inch pipe and not terminal blockage,
				replace blower.
		B)	Air pressure switch defective	Replace switch.
		C)	Gas valve defective	Replace gas valve.
		D)	Control harness defective	Replace harness.
		E)	Igniter defective	Replace igniter.
		F)	Unit has completed three trials to light	Reset cycle by turning switch off and then back on. If unit
			and failed	does not light in three trials, call an authorized A.O. Smith
				service representative.
		G)	Discharge air limit tripped	Verify dilution air openings are free of obstructions.
NOT ENOUGH OR				Make sure there is no more than 30 equivalent feet of 3 inch pipe or
				85 equivalent feet of 4 inch pipe.
NO HOT WATER
				Check for low voltage, less than 102 vac., have service
				checked and repaired.
				Make sure vent terminal is not blocked.
	3)	Thermostat problems
		A)	Thermostat set too low	Turn temperature control higher.
		B)	Thermostat or ECO defective	Replace thermostat.
		C)	High limit control circuit open	Replace.
	4)	Others
		A)	Heater undersized	Reduce hot water use.
		B)	Low gas pressure	Contact an authorized A.O. Smith service representative.
		C)	Incoming water is unusually cold	Allow more time for heater to re-heat.
		D)	Leaking hot water pipes or fixtures	Have plumber check and repair leaks.
		E)	Polarity reversed	Correct wiring
		F)	Heater not grounded	Correct
		A)	Blower does not run when heater fired	Take unit out of service immediately, call an authorized A.O.
VENT PIPE TOO HOT				Smith service representative.
		B)	Not enough dilution air to mix with flue	Proper air circulation must be provided for combustion and
(ABOVE 170° F)			gases in “Tee”	dilution of flue temp. Refer to “INSTALLATION” section.
		C)	Air in room too hot for mixing with flue gases	Room air to be used for dilution with combustion products in
				flue should be less than 90°F.
		D)	Wrong burner orifice	Install correct orifice.
YELLOW FLAME		A)	Dirt in burner ports	Turn off heater and gas, clean burner head.
		B)	Combustion air path restricted	Clear area around heater and check under heater, remove
				any debris under heater and in openings in bottom cover.
		C)	Not enough room air for proper combustion	Refer to installation manual - Confined and Unconfined Space
				statements on page 4 and 5 for required openings.
CONDENSATION		A)	Water on the floor under heater	See “CONDENSATION.”
	Improperly sealed, hot or cold supply connections,			Turn off heater & water, repair unit.
WATER LEAKS	relief valve, drain valve or thermostat threads
	Leakage from other appliances or water lines			Inspect other appliances near water heater.
	Condensation of flue products			Refer to “CONDENSATION.”
LEAKING T&P VALVE	Thermal expansion in closed water system			Install thermal expansion tank (DO NOT plug T&P valve).
	Improperly seated valve			Check relief valve for proper operation (DO NOT plug T&P valve).
HOT WATER ODORS OR COLOR	High sulfate or mineral content in water supply or			Drain and flush heater thoroughly, chlorinate, refill and flush
(RefertoCATHODICPROTECTION)	iron or sulfate reducing bacteria in water supply			again then chlorinate water supply.
HEATERLIGHTGOESOUT	Outlet polarity is reversed			Test polarity and correct.
IN 4-5 SECONDS

17