Your boiler's internal electronic brain has encountered a serious error and is unable to operate safely, causing the system to shut down.

Internal fault (PCB)

What causes this fault?

This fault occurs when the boiler's main control board suffers a critical electronic failure or a loss of communication between internal components. It is often caused by a voltage surge in the mains electricity or by moisture getting onto the circuitry, which prevents the board from safely managing the boiler's functions.