BoilerFaultCodesWhat the manual says
Manufacturer manualFan on
What causes this fault?
This fault occurs when the boiler's internal computer signals the fan to start, but fails to receive confirmation that air is moving through the system to safely clear waste gases. It is usually caused by a mechanical failure of the fan motor, a blockage in the flue, or a faulty sensor failing to detect the airflow.
This issue is slightly more common in autumn and winter, as debris like fallen leaves or nesting material can block the external flue pipe, preventing the required airflow.
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 LED3: no call-out fees, no surprise bills.
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