Your boiler's main control board has lost communication with its internal identity chip, effectively meaning the boiler has forgotten which model it is and cannot operate.

PCB personality chip fault

What causes this fault?

This fault occurs when the boiler's main control board loses its connection to the identity chip that tells it how to operate correctly. The most common reason is a hardware failure within the printed circuit board (PCB) or a loose connection to the data chip, often caused by age or electrical wear. In some cases, this can also happen after a replacement part has been installed but not correctly coded to the specific boiler model.