Your boiler's internal computer has encountered a serious error and can no longer control the system, meaning your heating and hot water will not work.

Internal fault (PCB)

What causes this fault?

This fault occurs when the boiler's internal computer, the Printed Circuit Board, suffers a critical electronic failure or a breakdown in communication with its sensors. The most common reason is general wear and tear of the electrical components, though power surges or moisture getting onto the board can also trigger this shutdown.