Furnace runs but carbon monoxide detector in the home alarms during 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
Emergency safety: Turn off the furnace immediately, open windows, evacuate if CO levels are high, and contact emergency services or your gas utility. Do not operate the furnace again until it has been inspected and cleared by a professional.
Do not attempt DIY repairs on heat exchangers or venting that affect combustion safety.
Repair Difficulty
Required Part
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