C6
Worcester Bosch Fan Speed / Air Pressure Switch Fault

Boiler shows C6, fan speed or air pressure issues detected.

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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.

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Possible Causes

Fan running at incorrect speed, Faulty fan speed sensor, Blocked flue, Faulty air pressure switch

How to Fix / Troubleshooting

Safety first: Do not remove the combustion cover or flue. Isolate power before any checks.

  • Visual flue check: Ensure the flue terminal is unobstructed and not damaged.
  • Reset boiler: Reset once and observe if the fan starts and runs smoothly.
  • Engineer tasks: An engineer should measure fan speed feedback, test the air pressure switch, inspect pressure tubing, and replace the fan or switch if required.
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Repair Difficulty

Professional Required 5/5

Required Part

Fan Assembly
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