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Rheem Error Code 12: Rheem Code 12 - Flame Failure
⚠️ 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.
What Does Rheem Error Code 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.
Common Causes of Rheem Code 12
- Gas supply issues (low gas pressure, shut-off valve closed)
- Blocked or partially blocked vent system restricting airflow
- Faulty flame sensor (dirty, mispositioned, or failing)
- Igniter malfunction (weak spark or no spark)
- Defective gas valve (not opening properly)
Applicable Rheem Models
Need a Pro to Fix Rheem Code 12?
This error requires immediate attention from a licensed HVAC technician. Do not attempt repair yourself.
Find a Licensed Tech Near You →Replacement Parts for Rheem Tankless Water Heater Code 12
Flame Sensor
Gas Valve
Igniter