Furnace ignites but produces yellow, lazy flames instead of blue
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: Yellow flames can indicate carbon monoxide production. Install and check CO detectors and avoid prolonged operation.
Steps to check (basic):
- Combustion air: Ensure combustion air openings to the furnace room are not blocked.
- Burner cleanliness: Visually inspect burners for heavy rust or debris.
When to call a professional: Combustion adjustment, burner cleaning, and flue inspection must be done by a licensed HVAC technician with proper instruments.
Repair Difficulty
Required Part
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