Furnace makes loud booming or banging noise at startup
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.
Possible Causes
How to Fix / Troubleshooting
Safety first: Booming ignition can be dangerous. Turn off gas and power and contact a qualified technician if the problem is severe.
User-level checks:
- Visual burner inspection: With power and gas off, remove burner access panel and inspect burners for rust, debris, or misalignment. Do not attempt gas pressure adjustments yourself.
- Ignitor condition: Check the ignitor for cracks or heavy white buildup. A weak ignitor may not light gas promptly and should be replaced.
Because delayed ignition involves combustion safety, a licensed HVAC technician should clean and adjust burners and verify gas pressure.
Repair Difficulty
Required Part
We may earn a commission from links on this page.