Your boiler is struggling to communicate with its internal air-flow system, which prevents it from safely igniting and providing heating or hot water.

Incorrect signal from fan

What causes this fault?

This fault occurs when the boiler's control board detects that the fan is not spinning at the required speed to safely clear exhaust gases. It is usually caused by a mechanical failure in the fan motor, a loose connection in the wiring, or a fault on the main circuit board failing to send the correct power signal.