BoilerFaultCodesTechnical 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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.