BoilerFaultCodesYour boiler has lost communication with your remote room thermostat or heating controller for the second heating circuit.
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: Control mode without remote control - Communication fault-Vitotrol remote control heating circuit M2
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
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like bd — no call-out fees, no surprises.
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Viessmann Vitodens 333 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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