34
Heil
Ignition Proving Failure
Heil furnace LED shows code 34; ignition fails or flame is lost shortly after lighting.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Dirty flame sensor, Poor burner ground, Low gas pressure, Partially plugged burner orifice
How to Fix / Troubleshooting
Safety: Turn off power and gas before servicing burners or flame sensor.
Steps to check:
- Clean flame sensor: Remove the sensor and polish the rod with fine steel wool. Reinstall and ensure the mounting screw is tight for good grounding.
- Check burner ground: Verify that the burner rack is securely fastened to the furnace chassis and that there is no heavy rust preventing good electrical contact.
- Inspect burner flames: After restoring power and gas, observe the flames. They should be steady and blue. Yellow, lazy, or lifting flames indicate combustion issues.
- Reset and test: Power cycle the furnace and call for heat to see if the code clears.
When to call a pro: If flame is unstable or goes out, a technician should check gas pressure, clean burners thoroughly, and verify proper venting and combustion air.
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Repair Difficulty
Medium
3/5
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