BoilerFaultCodesYour boiler has detected an issue with how it clears exhaust gases, which has caused it 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: Air Pressure Switch / Fan fault (Dip-switch #3 in off position).
What causes this fault?
This fault occurs when the boiler's internal safety sensor detects that the fan isn't moving enough air to safely clear exhaust fumes from the flue. It is often caused by a failing fan motor, a blocked air pipe, or a build-up of dirt within the small tubes that measure air pressure. Because the boiler cannot guarantee that waste gases are being removed, it shuts down immediately as a safety precaution.
This issue can be 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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