Your boiler has stopped working because it cannot detect that the internal fan, which is essential for safely venting exhaust gases, is running.

No signal from fan

What causes this fault?

This fault occurs when the boiler's computer loses contact with the fan responsible for clearing exhaust gases. It is usually caused by a mechanical failure within the fan motor itself or a loose connection in the internal wiring. Because the boiler cannot confirm the fan is spinning safely, it shuts down immediately as a safety precaution.