Your boiler has lost its connection with the external remote controller, meaning they are unable to talk to each other to manage your heating.

Appliance is connected to the optional remote control (RC05) and there is a communication problem.

What causes this fault?

This fault occurs when the boiler's main internal computer loses its digital handshake with the wall-mounted remote control unit. The most common reason is a loose connection in the wiring between the two devices or a component failure within the remote control unit itself that stops it from sending or receiving signals. Without this vital link, the boiler cannot receive instructions on when to turn the heating on or off.