Your boiler's internal computer has lost its connection with the main control board, meaning the system cannot communicate correctly to heat your home.

Communication interrupted.

What causes this fault?

This fault occurs when the boiler's central brain loses its ability to talk to the other internal electronic components. It is usually caused by a loose connection in the internal wiring or a component failure on the main circuit board that prevents data from flowing through the system. Think of it like a loose HDMI cable on a TV; the power is on, but the picture cannot get through.