Your boiler's internal communication system has failed, meaning the different electronic parts are no longer talking to each other correctly.

Communications fault - LON communication module. Control mode

What causes this fault?

This fault occurs when the main control board loses its connection with the internal plug-in communication module. The most common reason is an electronic component failure within the module itself or a loose physical connection caused by vibrations over time. Without this link, the boiler's brain cannot send or receive the data it needs to operate safely, causing it to stop running.