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, turn off the furnace immediately, ventilate the home, and evacuate if levels are high. Do not operate the furnace until it has been inspected by a qualified HVAC technician.
Do not attempt DIY repairs on the heat exchanger or venting. A professional must:
- Test for flue gas spillage and draft.
- Inspect the Armstrong Air heat exchanger for cracks or corrosion.
- Verify vent sizing and termination.
- Adjust combustion and verify CO levels in the flue.
Repair Difficulty
Required Part
We may earn a commission from links on this page.