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 warning: If a CO detector alarms, evacuate the building immediately and call emergency services and your gas utility. Do not re-enter until cleared by authorities.
- Shut down furnace: Turn off power and gas to the furnace if it is safe to do so.
- Do not reset and reuse: Do not attempt to restart the furnace until it has been thoroughly inspected by a licensed professional.
CO issues must be addressed by a qualified technician; components such as the heat exchanger or vent system may require replacement.
Repair Difficulty
Required Part
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