A. O. Smith 8 flashes
A. O. Smith water heater 8 flashes: pilot valve may be stuck open
Short answer
Eight flashes only appears after the gas control knob has been turned to OFF and the thermopile keeps producing power. Either the thermopile is cooling down slowly, or the pilot is still burning because the pilot valve is stuck open. A stuck pilot valve means the gas valve must be replaced.
Eight flashes is unusual because it shows up after you have turned the heater off. The gas control is telling you it is still getting power from the thermopile when it should not be.
These codes apply to standard atmospheric A. O. Smith gas tanks with a status light on the gas control valve. Power vent, condensing and tankless models use different codes, so check the label on your heater if the pattern does not match.
If you smell gas, do not relight or reset anything and do not touch electrical switches. Leave the building and call your gas utility from outside.
How to check
- Make sure the gas control knob is set to OFF and wait one minute.
- Remove the outer burner door and look through the sight glass for a pilot flame.
- If you see a pilot flame with the knob OFF, the pilot valve is stuck open. Turn off the main gas supply to the heater and call a technician to replace the gas control valve.
- If there is no pilot flame, wait ten minutes for the thermopile to cool, then relight the pilot following the label. If eight flashes returns, the gas control valve needs to be replaced.
Why a stuck pilot valve matters
A pilot that keeps burning after the control is turned off means the valve is no longer fully in control of the gas. That is why the fix is always a new gas control valve.
Common questions
Is 8 flashes on an A. O. Smith water heater dangerous?
It can be. If the pilot is still lit with the knob off, turn off the main gas supply to the heater and have the gas valve replaced.
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Other A. O. Smith codes
| Code | Meaning |
|---|---|
| 0 flashes | Light off: pilot out or thermopile not yet warm |
| Solid red | Solid red light: pilot recently went out, thermopile cooling |
| 2 flashes | Pilot lit but thermopile output too low |
| 4 flashes | Water temperature too high (high limit tripped) |
| 5 flashes | Temperature sensor (thermistor) failure |
| 7 flashes | Gas control valve failure |
| 8 flashes | Thermopile still producing power with the knob off (pilot valve may be stuck open) |