Worcester Bosch Fan Speed / Fan Running Too Slowly

Boiler shows C6, often with noisy fan operation or failure to ignite.

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

Worn fan bearings, Obstruction in fan or flue, Faulty fan speed sensor, PCB modulation fault

Safety first: Isolate power and gas. The fan is within the sealed combustion chamber.

Listen for unusual noises: Grinding or whining from the fan area indicates bearing wear and impending failure.
Check flue terminal: Ensure no external obstruction is causing back pressure.
Engineer tasks: A Gas Safe engineer should measure fan speed, inspect for debris, check the flue for blockages, and replace the fan if it cannot reach the required speed.

Professional Required 5/5

Combustion Fan Assembly

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