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Ruud Error Code 12: Flame Failure

⚠️ A 'Flame Failure' error indicates a potential gas leak or carbon monoxide risk. Shut down the unit immediately and call a qualified HVAC technician.

How to Fix Ruud Code 12

  1. Step 1: Turn off the furnace immediately at the breaker. This will stop the flow of gas to the unit.
  2. Step 2: Ensure that all vents around the furnace and outside are clear of obstructions like snow, ice, or debris.
  3. Step 3: Check your home's carbon monoxide detectors to ensure they are functioning correctly. Replace batteries if needed.
  4. Step 4: Call a qualified HVAC technician to inspect the furnace and diagnose the root cause of the flame failure.
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What Does Ruud Error Code 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.

Common Causes of Ruud Code 12

  • Dirty or faulty flame sensor
  • Gas valve malfunction (not opening or opening intermittently)
  • Ignition failure (failed igniter or spark)
  • Insufficient gas pressure
  • Blocked or restricted flue/venting system
  • Faulty control board

Applicable Ruud Models

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Need a Pro to Fix Ruud Code 12?

This error requires immediate attention from a licensed HVAC technician. Do not attempt repair yourself.

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Replacement Parts for Ruud HVAC System Code 12

Flame Sensor OEM: 47-21501-03
Gas Valve OEM: 7000BM1624
Hot Surface Igniter OEM: 41-413