BoilerFaultCodesYour boiler has detected an issue with the ventilation fan or airflow, causing the system to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Go to Fan Lockout section of the fault finding instructions.
What causes this fault?
This fault occurs when the boiler's internal computer detects that the ventilation fan is not spinning at the correct speed or the airflow is blocked. Without a functional fan to clear away combustion gases, the boiler automatically shuts down to prevent dangerous fumes from building up inside the unit. The most common reasons are a seized fan motor, a perished vacuum tube, or a sensor that has failed to detect the air movement.
This issue is slightly more frequent in autumn and winter, as heavy winds can sometimes create back-pressure in the flue or debris like leaves can obstruct the external air intake.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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