Furnace operates but carbon monoxide detector in the home alarms during or shortly after operation.
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
Immediate safety: Turn off the furnace and all fuel-burning appliances. Open windows and doors to ventilate. Evacuate if anyone feels unwell and call emergency services.
Do NOT restart the furnace until it has been inspected.
Professional tasks only: A licensed technician must inspect the flue, heat exchanger, and combustion settings with proper instruments. Components such as the heat exchanger or burner may need replacement.
Repair Difficulty
Required Part
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