BoilerFaultCodesYour boiler has detected a problem with how air and waste gases are moving through the system, causing 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 fault
What causes this fault?
This fault occurs when the boiler's safety sensors detect that the fan isn't moving enough air to safely vent exhaust gases out of the flue. The most common reasons are a blockage in the air pipes, a failing fan motor, or the internal pressure switch simply getting stuck over time.
This fault is slightly more common during periods of heavy wind or storms, as high pressure against the external flue pipe can interfere with the boiler’s ability to circulate air.
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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A boiler cover plan would cover faults like F3 — no call-out fees, no surprises.
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