BoilerFaultCodesYour boiler has detected an issue with how it breathes, meaning it cannot safely remove exhaust fumes or pull in fresh air.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: AIR FLOW SAFETY: CHECK THE FLUE SYSTEM FOR A BLOCKAGE, EXCESS LENGTH. CHECK THE AIR PRESSURE SWITCH. CHECK THE ELECTRICAL CONNECTIONS.
What causes this fault?
This fault occurs when the boiler's internal safety sensors detect that the fan isn't moving air through the system effectively enough to operate safely. The most common reasons are a physical blockage in the flue pipe outside, a build-up of dirt inside the fan, or a failure in the small rubber tubes that monitor air pressure.
This issue can be more frequent during periods of high winds or extreme cold, which can cause external flue obstructions or pressure fluctuations that trigger the safety sensor.
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 02 — no call-out fees, no surprises.
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