Gas Water Heater Error Codes and Flashing Lights
On this page (5 sections)
The Short Answer: There is no universal code chart for gas water heaters. The flash count on a tank’s gas control comes from the control maker (Honeywell/Resideo, White-Rodgers, or a brand’s own design), and the same count can mean different things on different controls. Read the label on your heater, record the exact pattern, and use the guide for your brand.
Where the code comes from
On most gas tanks with a status light, the light is on the gas control valve at the front of the heater, not on the tank itself. Power-vent and high-efficiency models may have a separate display or a light on the blower assembly. The label on or near the control explains the patterns for that control.
Even within one control maker, versions differ. Bradford White’s service manual 238-51542-00A (opens in a new tab) has a chart for the Honeywell control on those models: one flash every three seconds is normal operation, a solid light after turning the knob to OFF means wait until it goes out before relighting, and higher counts indicate faults such as low thermopile voltage or excessive tank temperature. A different control, or an older version of the same one, can assign those counts differently.
How to record the code
- Watch the light through at least two full cycles. Count the flashes between pauses.
- Note the color if the light changes color.
- Photograph the rating plate and the label on the gas control.
- Note what the heater was doing: pilot lit or out, main burner on or off, blower running or not.
That information lets a technician or the manufacturer’s support line identify the fault without guessing.
What codes generally point to
Without assigning numbers, the faults gas controls report fall into a few groups:
| Fault group | Typical owner action |
|---|---|
| Normal operation or standby | None |
| Pilot weak, thermopile low, or flame not proven | Relight once per the label; service if it repeats |
| Tank too hot or temperature sensor fault | Turn the heater off; service |
| Airflow or pressure switch fault (power-vent) | Check power and the outside vent; service if it repeats |
| Flammable vapor sensor or thermal switch tripped | Remove any stored fuel or solvents; service |
| Internal control fault | Service; the control may need replacing |
Brand-specific guides
- Rheem, Ruud and Richmond: Rheem flashing blue light 7 times
- A. O. Smith and State: AO Smith blinking green light
- Bradford White: weak pilot signal
- Controls with no brand match: Honeywell water heater reset
Frequently Asked Questions
Q: Can I clear a gas water heater code myself? A: You can follow the lighting or restart steps printed on the label once, after fixing an obvious cause like a closed gas valve. If the code returns, the cause is still there and needs a technician.
Q: My heater has no status light. How do I tell what is wrong? A: Many standard tanks have no light. Use the symptom instead: pilot won’t light, pilot won’t stay lit, or burner lights then goes out. See why won’t my gas water heater stay lit.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Bradford White: service manual 238-51542-00A (Honeywell gas control troubleshooting chart) (opens in a new tab)Bradford White FVIR gas models covered by that manual with a Honeywell gas control.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
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