BoilerFaultCodesWhat the manual says
Manufacturer manualFault on Fan or Flue
What causes this fault?
This fault occurs when the boiler's safety system detects that the fan isn't spinning fast enough or that exhaust gases aren't being pushed out of the flue correctly. It is often caused by a mechanical failure in the fan motor, a blockage in the flue pipe, or debris trapped in the small tubes that monitor airflow.
This issue can become more frequent during periods of high winds, which can create back-pressure in the flue and interfere with the air pressure sensor's readings.
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.
Avoid the next call-out bill
A cover plan would handle faults like 25: no call-out fees, no surprise bills.
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