Your boiler has stopped working because the internal fan, which safely pushes exhaust gases out of the flue, is not spinning at the correct speed.

Fan speed incorrect. Check fan wiring and connections. Replace fan Part No. 5106068 or boiler control

What causes this fault?

This fault occurs when the boiler’s internal computer detects that the fan is not spinning at the required speed to safely clear waste gases from the system. The most common reason is that the fan motor has physically burnt out or become seized, though it can also be caused by loose wiring or a failing control board that is sending incorrect signals to the motor.