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 moving enough air to safely vent exhaust gases out of the flue. The most common reasons are a build-up of dirt in the fan or small tubes, a mechanical failure of the fan motor, or an electrical fault where the control board can no longer communicate with the air sensors.
This issue can occasionally follow periods of high winds or heavy rain, which may cause debris or moisture to interfere with the delicate sensors and tubes connected to the flue.
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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