Thermia Delayed Ignition / Burner Explosion Noise

Furnace makes loud banging or booming noises at startup.

Advertisements

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.

Advertisements

Possible Causes

Dirty burners, Misaligned burner orifices, Low gas pressure, Weak hot surface igniter on Thermia burner assembly

How to Fix / Troubleshooting

Safety first: Turn off power and gas. Do not continue to operate a furnace that booms at startup.

  • 1. Inspect burners: Remove and visually inspect the Thermia burner assembly for rust, debris, or blocked ports.
  • 2. Clean burners: Use compressed air and a soft brush to clean burner ports and crossover channels. Reinstall carefully, ensuring proper alignment.
  • 3. Check igniter position: Confirm the hot surface igniter is correctly positioned to light the gas quickly.
  • 4. Professional gas check: Have a licensed technician verify gas pressure and combustion. Do not attempt to adjust gas pressure yourself.
Advertisements

Repair Difficulty

Professional Required 5/5

Required Part

Burner Assembly
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements