Ruud Error Code 12: Flame Failure
How to Fix Ruud Code 12
- Step 1: Turn off the furnace immediately at the breaker. This will stop the flow of gas to the unit.
- Step 2: Ensure that all vents around the furnace and outside are clear of obstructions like snow, ice, or debris.
- Step 3: Check your home's carbon monoxide detectors to ensure they are functioning correctly. Replace batteries if needed.
- Step 4: Call a qualified HVAC technician to inspect the furnace and diagnose the root cause of the flame failure.
How to Reset Ruud Code 12
- Turn off the furnace power switch, usually located on or near the unit.
- Turn off the circuit breaker for the furnace. Wait 30 seconds.
- Restore power at the breaker and flip the furnace switch back on.
- Set the thermostat to call for heat. If the error code returns after 2-3 ignition attempts, the fault requires repair.
What does 12 mean?
The Ruud furnace error code 12, 'Flame Failure,' means the furnace tried to light the burners, but the flame wasn't detected by the flame sensor. This can happen during startup or even while the furnace is running. The control board constantly monitors the flame sensor signal. If the flame isn't sensed when it should be, the furnace shuts down as a safety precaution to prevent unburned gas from accumulating, which could lead to a dangerous situation.
This error is critical because it involves gas and combustion. A flame failure can be caused by a variety of issues, ranging from a dirty flame sensor to a problem with the gas valve or even the venting system. Because of the potential safety hazards, it's important to address this issue promptly and correctly.
Affected Models
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Flame Sensor | 47-21501-03 | — |
| Gas Valve | 7000BM1624 | — |
| Hot Surface Igniter | 41-413 | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| 11 | No Ignition | Critical |
| 13 | Improper Combustion | Critical |
| 14 | Overheat / Thermal Fuse | Critical |
| 15 | Inlet Temp Sensor Fault | Warning |
| 16 | Outlet Temp Sensor Fault | Warning |
| 21 | Air Supply / Operational Switch | Warning |
| 24 | Flow Sensor Malfunction | Warning |
| 29 | Condensate Neutralizer Issue | Warning |
| 31 | Inlet Water Filter | Warning |
| 33 | Fan Motor Fault | Warning |