Reliance gas water heaters use the same LED flash code system as the rest of the AO Smith family (same gas valve hardware from AO Smith manufacturing). Count the flashes between pauses to read the code.
The flash codes
| Flashes | Meaning | Action |
|---|---|---|
| 1 flash steady | Normal operation | Status indicator — no fault |
| 2 flashes | Thermopile / pilot voltage low | Clean intake; replace thermocouple |
| 3 flashes | Inlet thermistor (some models) | Sensor test or replacement |
| 4 flashes | High-temp lockout / ECO trip | Check water flow, ECO reset, thermostat |
| 5 flashes | Vacuum switch / draft | Inspect chimney or vent termination |
| 6 flashes | FVIR flammable vapor sensor | Clear vapors; reset |
| 7 flashes | Gas valve fault | Dealer replacement |
| 8 flashes | Combustion air switch / intake blocked | Clean FVIR intake screen at base |
How to read the code
- Remove the burner access cover (lower front of tank) or look at the gas valve from below
- Watch the small status LED for several seconds
- Count rapid flashes, then notice the pause
- Number of flashes before the pause = the code
- Pattern repeats every 5-10 seconds
How to reset
- Gas valve reset: rotate dial to "Off," wait 5 minutes, rotate to "Pilot" or "On"
- ECO reset (electric): red button on upper thermostat (under upper access cover)
- Power cycle: breaker off 30 seconds for power-vent and electric units
Electric Reliance diagnostics
Electric units don\'t have an LED code system. Diagnose by breaker check, ECO reset, then multimeter testing of elements and thermostats. Same approach as State and AO Smith Signature electric.
Hybrid Heat Pump (HPHE) diagnostics
HPHE units have a digital display panel with alphanumeric codes:
- P1 / P2 — temperature sensor fault
- F1 / F2 — control board fault
- HP — heat pump compressor lockout (reverts to electric resistance)
- EL — element fault on resistance backup
- HE — high-temperature alarm (check air space)
- CO — condensate drain blocked
Mini-Tank (SOMS) diagnostics
Mini-tanks have an ECO reset on the rear panel. No LED display. If no hot water, check 120V outlet power → reset ECO → ohms-test the small 1500W element.
Bottom line
Gas: count LED flashes on gas valve. Electric: ECO reset + multimeter. Hybrid: digital display with AO Smith heat pump codes. Mini-tank: 120V + ECO reset.