Furnace starts but shuts down immediately when blower starts
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: A cracked heat exchanger can leak carbon monoxide. If you suspect this, shut down the furnace and do not operate it.
Steps to check (basic):
- Filter and ducts: Ensure filter is clean and ducts are not blocked.
- CO detectors: Verify carbon monoxide detectors are installed and functioning.
When to call a professional: Heat exchanger inspection and combustion testing must be performed by a qualified HVAC technician.
Repair Difficulty
Required Part
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