Your boiler's internal computer boards are having trouble communicating with each other, preventing the system from starting up.

Main PCB / Display PCB fault

What causes this fault?

This fault occurs when the boiler's main control board loses the ability to send or receive electronic signals from the display screen panel. It is usually caused by a loose internal connection or a microscopic failure in the electrical circuits on one of the boards. Without this constant 'handshake' between components, the boiler cannot verify that the settings are safe and will stop working immediately.