Your boiler has stopped working because the internal fan, which safely clears exhaust gases, isn't spinning or communicating correctly with the system.

fan error

What causes this fault?

This fault occurs when the boiler's control system detects that the fan is either not spinning fast enough or has stopped altogether. The most common reason is a mechanical failure of the fan motor or a buildup of dust and debris that prevents it from rotating freely. In some cases, the main circuit board may be failing to send power or signals to the fan, causing the boiler to shut down for safety.