BoilerFaultCodesWhat the manual says
Manufacturer manualAir flow rate safety device: Obstruction of the flue occurs; fan will continue to run but boiler turns OFF.
What causes this fault?
This fault occurs when the boiler's safety sensors detect that harmful exhaust gases are not being cleared from the system effectively. The most common reasons are a mechanical failure of the fan, a blockage in the external flue pipe, or a perished internal seal that is leaking air.
This issue can occur during periods of high winds, which may create a back-pressure in the flue that prevents the fan from extracting gases correctly.
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.
Avoid the next call-out bill
A cover plan would handle faults like Red flashing light (Flue): no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.