BoilerFaultCodesYour boiler has detected an issue with the airflow system, which is preventing the burner from lighting for safety reasons.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Air Pressure Switch neon status. If not lit, check fan and 240V supply to fan.
What causes this fault?
This fault occurs when the boiler's safety sensors cannot confirm that the fan is successfully pushing exhaust fumes out of the flue. The most common reasons are a buildup of debris in the fan or air tubes, or the mechanical switch itself failing to register the flow of air. Until the boiler is certain it can vent gases safely, it will prevent the burner from firing.
This issue is frequently seen during periods of high wind, which can create back-pressure in the flue that interferes with the sensitive air pressure switch.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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