Furnace starts normally but shuts off when the blower comes on.
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
Safety first: This symptom can indicate a cracked heat exchanger. Carbon monoxide risk is possible.
- Check filter and registers: Ensure proper airflow to reduce pressure changes.
- Room pressure: Make sure the furnace room has adequate combustion air and is not tightly sealed.
Because of potential heat exchanger failure, shut down the furnace and have a licensed technician perform a combustion and heat exchanger inspection.
Repair Difficulty
Required Part
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