How to Fix / Troubleshooting

Safety: Isolate power before removing the combustion cover.

Check for obstruction: Remove the fan assembly cover (if accessible) and inspect the impeller for debris or signs of rubbing. Clear any obstruction.
Spin test: Gently rotate the fan impeller by hand. It should turn freely without grinding. A stiff or noisy fan indicates bearing failure.
Electrical checks: Verify that the fan connector is fully seated on the Baxi PCB and that there are no burnt pins. A technician can measure supply voltage to the fan during startup.
Replace if faulty: If the fan is seized or not receiving correct control signals, replacement of the combustion fan assembly is required.

Note: Fan replacement affects combustion characteristics and should be commissioned by a qualified engineer.

Furnace shows fan fault, fan does not start or runs erratically during startup

Possible Causes