Technical description
Fan problem. If the fan does not work properly, the appliance will switch itself off.
What causes this fault?
This fault occurs when the boiler's control set cannot reach the required fan speed to safely move air through the system. The most common reasons include a buildup of debris or moisture damaging the fan's motor, or a communication failure where the main circuit board can no longer 'talk' to the fan. Without a functioning fan to clear exhaust gases, the boiler will refuse to ignite for safety reasons.
This fault can be more common in winter when heavy winds or driving rain enter the flue terminal, causing moisture to damage the fan's electronic components.
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.