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WARNING: DO NOT
TROUBLESHOOTING
For your safety, water heater service should be performed only by a qualified service technician.
Read the GENERAL SAFETY INFORMATION section first.
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| POSSIBLE MALFUNCTION | SERVICE TO BE PERFORMED |
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| 1) | Blower will not run |
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| A) | “ON/OFF” control switch turned off | Turn switch to the “ON” position. | |||
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| B) | Blower unplugged | Plug blower back into 115 vac. outlet. | |||
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| C) | No power at outlet | Repair service to outlet. | |||
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| D) | “ON/OFF” switch defective | Replace switch. |
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| E) | Control harness defective | Replace control harness. | |||
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| F) | Blower motor defective | Replace blower and motor. | |||
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| 2) | Blower running, burner not on | Replace switch. | ||||
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| A) | Fan not running fast enough to close | Check for low voltage, less than 102 vac., have service | |||
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| air switch contacts |
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| If voltage is above 102 vac., make sure there is not more than | ||
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| 30 Equivalent feet of 3 inch pipe or 85 equivalent feet of 4 inch | ||
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| pipe installed or vent terminal blockage. | ||
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| If at least 102 vac., less than 30 equivalent feet of 3 inch pipe |
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| or 85 equivalent feet of 4 inch pipe and not terminal blockage, | ||
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| replace blower. | ||
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| B) | Air pressure switch defective | Replace switch. | |||
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| C) | Gas valve defective | Replace gas valve. | |||
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| D) | Control harness defective | Replace harness. | |||
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| E) | Igniter defective | Replace igniter. | |||
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| F) | Unit has completed three trials to light | Reset cycle by turning switch off and then back on. If unit | |||
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| and failed | does not light in three trials, call an authorized A.O. Smith | |||
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| service representative. | ||
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| G) | Discharge air limit tripped | Verify dilution air openings are free of obstructions. | |||
| NOT ENOUGH OR |
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| Make sure there is no more than 30 equivalent feet of 3 inch pipe or | ||
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| 85 equivalent feet of 4 inch pipe. | |||
| NO HOT WATER |
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| Check for low voltage, less than 102 vac., have service | |||
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| checked and repaired. |
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| Make sure vent terminal is not blocked. | ||
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| 3) | Thermostat problems |
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| A) | Thermostat set too low | Turn temperature control higher. | |||
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| B) | Thermostat or ECO defective | Replace thermostat. | |||
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| C) | High limit control circuit open | Replace. | |||
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| 4) | Others |
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| A) | Heater undersized | Reduce hot water use. |
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| B) | Low gas pressure | Contact an authorized A.O. Smith service representative. | |||
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| C) | Incoming water is unusually cold | Allow more time for heater to | |||
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| D) | Leaking hot water pipes or fixtures | Have plumber check and repair leaks. |
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| A) | Blower does not run when heater fired | Take unit out of service immediately, call an authorized A.O. |
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| Smith service representative. |
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| B) | Not enough dilution air to mix with flue | Proper air circulation must be provided for combustion and | |||
| VENT PIPE TOO HOT |
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| gases in “Tee” | dilution of flue temp. Refer to “INSTALLATION” section. | |||
| (ABOVE 170° F) |
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| C) | Air in room too hot for mixing with flue gases | Room air to be used for dilution with combustion products in |
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| flue should be less than 90°F. | |||
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| D) | Wrong burner orifice | Install correct orifice. |
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| A) | Dirt in burner ports | Turn off heater and gas, clean burner head. | |||
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| B) | Combustion air path restricted | Clear area around heater and check under heater, remove | |||
| YELLOW FLAME |
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| any debris under heater and in openings in bottom cover. | ||
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| C) | Not enough room air for proper combustion | Refer to installation manual - Confined and Unconfined Space | |||
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| statements on page 4 and 5 for required openings. | ||
| CONDENSATION |
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| A) | Water on the floor under heater | See “CONDENSATION.” |
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| B) | Water dripping from fan | Provide drip “TEE” to catch condensation, refer to pages 8 and 10. | ||||
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| Improperly sealed, hot or cold supply connections, | Turn off heater & water, repair unit. | |||||
| WATER LEAKS |
| relief valve, drain valve or thermostat threads |
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| Leakage from other appliances or water lines | Inspect other appliances near water heater. |
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| 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). |
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| Improperly seated valve | Check relief valve for proper operation (DO NOT plug T&P valve). | ||||||
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| HOTWATERODORSORCOLOR |
| High sulfate or mineral content in water supply or | Drain and flush heater thoroughly, chlorinate, refill and flush | |||||
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| iron or sulfate reducing bacteria in water supply | again then chlorinate water supply. | ||||||
| (RefertoCATHODICPROTECTION) |
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