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
Critical safety warning: If a CO detector alarms, immediately turn off the furnace, open windows, evacuate occupants, and call emergency services or your gas utility. Do not operate the furnace until it has been inspected and cleared by a qualified technician.
- Do not attempt DIY repair: Heat exchanger and venting defects require professional tools and expertise.
- Document alarm events: Note the time, duration, and which detectors activated to assist the technician.
Repair Difficulty
Required Part
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