Your boiler has detected an internal error within its main electronic brain, causing it to stop running for safety.

Internal fault in burner controller.

What causes this fault?

This fault occurs when the boiler's main control board fails its internal safety self-checks, essentially meaning the 'brain' of the unit has developed a communication error or hardware failure. It is usually caused by a component failure on the circuit board itself or, more rarely, by an electrical surge that has damaged the delicate sensors.