Technical description
Internal fault (PCB)
What causes this fault?
This fault occurs when the boiler's internal computer brain suffers a hardware failure, meaning it can no longer safely coordinate the various sensors and components. The most common reasons include standard wear and tear of electronic capacitors or damage caused by an external electrical power surge. Because the control board is the central processing unit, the boiler shuts down immediately as it can no longer guarantee safe operation.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.