BoilerFaultCodesWhat the manual says
Manufacturer manualFan speed too high.
From this model's manual
Verified against the Worcester Bosch Greenstar 30he installation & service manual.
What causes this fault?
This fault occurs when the boiler's internal computer detects that the fan is spinning at a higher speed than required for safe combustion. It is typically caused by a faulty sensor within the fan motor itself or a communication error from the main control board, which prevents the boiler from regulating the airflow correctly.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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