Medium Warning
bd on Viessmann Vitodens 333

Your boiler has lost communication with your remote room thermostat or heating controller for the second heating circuit.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Communication fault - Vitotrol remote control heating circuit M2. Control mode without remote control

What causes this fault?

This fault occurs when the boiler's main internal computer loses its connection with the remote thermostat or controller managing your second heating circuit. The most common reason is an electrical break in the wiring between the units, a loose connection, or a hardware failure within the communication module itself.

DIY fix possible

Check if the batteries in your wall-mounted thermostat need replacingEnsure the thermostat is within signal range of the boilerTurn the boiler off and back on at the fused spur switch to reset the connection

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