BoilerFaultCodesYour boiler has detected a problem safely moving waste gases out through the flue pipe, 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 not proved.
What causes this fault?
This fault occurs when the boiler's internal safety sensor cannot detect the flow of air needed to clear away fumes. The most common reasons are a cooling fan that has become stuck or dirty, a blockage in the flue pipe outside, or small internal tubes becoming perishd or clogged with debris.
This issue is more frequent during periods of high winds or extreme cold, which can put extra strain on the fan or cause external flue obstructions.
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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