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TROUBLE SHOOTING (Continued)
PROBLEM CAUSE SOLUTION
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) Thermostat defective. Replace thermostat.
E) Control harness defective. Replace control harness.
F) High limit control circuit open. Replace ECO.
NOT ENOUGH G) Blower motor defective. Replace Blower Assembly.
HOT WATER Thermostat problems.
A) Thermostat set too low. Set temperature control higher.
B) Thermostat or ECO defective. Replace thermostat or ECO as required.
Others
A) Heater undersized. Reduce hot water use.
B) Low gas pressure. Contact dealer.
C) Incoming water is unusually cold. Allow more time for heater to reheat.
D) Leaking hot water pipes or fixtures. Have plumber check and repair leaks.
A) Defective air flow restrictor. Take unit out of service immediately, call an
A.O. Smith service representative.
B) Not enough dilution air to mix with Proper dilution air must be provided for
flue gases in inlet tee. combustion and dilution of flue temp.
VENT PIPE TOO HOT Refer to “INSTALLATION” section.
(ABOVE 170°F) C) Dilution air too hot for mixing with Supply air is too hot. Check for heat sources
flue gases. around intake terminal and blockage of
dilution air leg.
D) Wrong burner orifice. Install correct orifice.
A) Dirt in burner ports Turn off heater and gas, clean burner head.
B) Combustion air path restricted. Check intake venting arrangements for
YELLOW FLAME obstructions.
C) Not enough dilution air for proper Check Intake venting arrangement for
combustion. obstructions.
A) Water on the floor under heater. See “CONDENSATION” section.
CONDENSATION B) Water dripping from pan. Provide drip “TEE” to catch condensation,
see Figure 1.
Improperly sealed, hot or cold supply
connections, relief valve, drain valve Tighten threaded connections.
WATER LEAKS or thermostat threads.
Leakage from other appliances or water Inspect other appliances near water heater.
lines.
Condensation of flue products. Refer to “CONDENSATION” section.
Thermal expansion in closed water Install thermal expansion tank (DO NOT plug
LEAKING T&P system. T&P valve).
Improperly seated valve. Check relief valve for proper operation
(DO NOT plug T&P valve).
HOT WATER ODORS High sulfate or mineral content in Drain and flush heater thoroughly then refill.
(Refer to CATHODIC water supply.
PROTECTION) Bacteria in water supply. Chlorinate water supply.
WATER TOO HOT Thermostat set too high. Refer to TEMPERATURE REGULATION.
WATER HEATER SOUNDS Condensation dripping on burner. Refer to CONDENSATION above.
SIZZLING-RUMBLING Sediment at bottom of heater tank. Clean sediment from tank. Refer to DRAINING
instruction in Maintenance section of manual.
SOOTING Improper combustion. Refer to COMBUSTION AIR AND EXHAUST on
page 6.
HEATER LIGHTS BUT GOES Outlet polarity is reversed. Test polarity and correct.
OUT IN 4-5 SECONDS