A.O. Smith GPD-40 Instruction Manual page 33

TROUBLESHOOTING GUIDELINES TROUBLESHOOTING GUIDELINES
These guidelines should be utilized by a qualifi ed service agent. When calling for service notify the service agent
PROBLEM
NOT ENOUGH OR
NO HOT WATER
VENT PIPE DEFORMED
OR DISCOLORED
YELLOW FLAME
CONDENSATION
WATER LEAKS
LEAKING T & P VALVE
HOT WATER ODORS (Refer to
CATHODIC PROTECTION)
WATER TOO HOT
WATER HEATER SOUNDS
SIZZLING - RUMBLING
SOOTING
HEATER LIGHT GOES OUT
IN 4–5 SECONDS
VENT GAS ODORS
that this is a "Flammable Vapor Ignition Resistant" Product.
CAUSE
1. Blower will not run.
A) "ON/OFF" control switch turned off.
B) Blower unplugged.
C) No power at outlet.
D) Thermostat defective.
E) Control harness defective.
F) High limit control circuit open.
G) Blower motor defective.
2. Thermostat problems
A) Thermostat set too low.
B) Thermostat or ECO defective.
3. Others
A) Heater undersized.
B) Low gas pressure.
C) Incoming water is unusually cold.
D) Leaking hot water pipes or fi xtures.
Defective air fl ow restrictor.
Not enough dilution air to mix with fl ue gases in inlet elbow.
Dilution air too hot for mixing with fl ue gases.
Wrong burner orifi ce.
Dirt in burner ports.
Combustion air path restricted.
Not enough dilution air for proper combustion.
Water on the fl oor under heater.
Water dripping from blower assembly.
Improperly sealed hot or cold supply connections, relief
valve, drain valve or thermostat threads.
Leakage from other appliances or water lines.
Condensation of fl ue products.
Thermal expansion in closed water system.
Improperly seated valve.
High sulfate or mineral content in water supply.
Bacteria in water supply.
Thermostat set too high.
Condensation dripping on burner.
Sediment at bottom of heater tank.
Improper combustion.
Outlet polarity is reversed.
Lack of air supply.
Improperly installed vent piping.
Downdraft.
Poor Combustion.
Turn switch to the "ON" position.
Plug blower back into 115 vac. outlet.
Repair service to outlet.
Replace thermostat.
Replace control harness.
Replace ECO.
Replace blower assembly.
Turn temperature control higher.
Replace thermostat or ECO as required.
Reduce hot water use.
Contact dealer.
Allow more time for heater to reheat.
Have plumber check and repair leaks.
Take unit out of service immediately; call a service
representative.
Proper dilution air must be provided for combustion and dilution of
fl ue temperature. Refer to the "INSTALLING THE NEW WATER
HEATER" section in the manual.
Supply air is too hot. Check for heat sources around intake
terminal and blockage of dilution air leg.
Install correct orifi ce.
Turn off heater and gas, clean burner head.
Check intake venting arrangement for obstructions.
Check intake venting arrangement for obstructions.
See "CONDENSATION" section.
Provide drip "TEE" to catch condensation from horizontal section
of exhaust vent close to blower assembly.
Tighten threaded connections.
Inspect other appliances near water heater.
See "CONDENSATION" section.
Install thermal expansion tank (DO NOT plug T & P valve).
Check relief valve for proper operation (DO NOT plug T & P
valve).
Drain and fl ush heater thoroughly then refi ll.
Chlorinate water supply.
Refer to "TEMPERATURE REGULATION" section.
See "CONDENSATION" section.
Clean sediment from tank. Refer to "DRAINING" instructions in
the "MAINTENANCE" section.
Refer to the "COMBUSTION AIR AND VENTILATION"
section.
Test polarity and correct.
Immediately shut down the water heater and contact a service
agency to determine cause.
33
SOLUTION