Rheem Error Code 12: Rheem Code 12 - Flame Failure
Warning: A Code 12 indicates a flame failure, which can lead to a dangerous buildup of unburnt gas. Shut down the unit immediately and call a qualified technician.
How to Fix Rheem Code 12
- Step 1: Ensure the gas supply to the unit is turned on. Check the shut-off valve on the gas line leading to the water heater.
- Step 2: Reset the unit by turning the power off and then back on. Wait a few minutes to see if the error code clears.
- Step 3: If the error persists after these steps, immediately call a qualified HVAC technician or plumber to inspect the unit. Do not attempt further troubleshooting yourself due to the risk of gas leaks or explosion.
How to Reset Rheem Code 12
- Turn off the unit using the power button on the front panel.
- Turn off the gas supply valve.
- Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
- Restore power at the breaker, then open the gas valve.
- Turn the unit back on. If the error returns, the underlying issue needs repair.
What does 12 mean?
Rheem tankless water heaters are designed with multiple safety features. A Code 12, or Flame Failure error, means the unit tried to ignite the burner, but the flame wasn't properly detected or was lost during operation. This is a critical safety issue because unburnt gas can accumulate inside the unit and potentially create a hazardous situation. The system locks out as a safety measure. This error can occur during initial startup, during normal operation, or after a period of inactivity. It's important to address this issue promptly to ensure safe and reliable hot water.
Affected Models
- R92V
- R92V
- R92E
- R92E
- R92E
- Rheem Classic Plus Series
- Rheem Classic Plus Series
- Rheem Classic 90 Plus
- Rheem Classic 80 Plus
- Rheem Prestige Series
- Rheem Classic Series
- Rheem Prestige Series
- Rheem Classic Series
- Rheem Classic Plus Series
- Rheem Classic Plus Series
- Rheem Prestige
- Rheem Classic
- Rheem Prestige Series
- Rheem Classic Series
- NCB
- NPE
- RNC
- RNG
- RNE
- Rheem Classic Series
- Rheem Classic Plus Series
- RNC
- RPB
- Rheem Prestige Series
- Rheem Classic Series
- RNC
- R801T
- R801T
- RH2T
- RP16
- RP16
- RTGH
- RGE
- Rheem Classic Plus Series
- Rheem Classic Plus Series
- Rheem Classic Series
- Rheem Classic Series
- Rheem Classic Plus Series
- Rheem Prestige Series
- Rheem Classic 80% Gas Furnace
- Rheem Prestige 95% Gas Furnace
- R92V
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Flame Sensor | — | — |
| Gas Valve | — | — |
| Igniter | — | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| A001 | Ignition Failure | Warning |
| A003 | Abnormal Ignition | Warning |
| A004 | False Flame Detection | Warning |
| A008 | Exhaust Temperature High | Warning |
| A011 | No Flame Detected | Warning |
| A021 | Over-Temperature | Warning |
| A031 | Inlet Thermistor Open/Short | Warning |
| A041 | Outlet Thermistor Open/Short | Warning |
| A043 | Water Level Error | Warning |
| A051 | Fan Motor Abnormality | Warning |