Low Warning
81:2 on Viessmann Vitodens 300-W

Your boiler is notifying you that it has detected and is automatically setting up its wireless clock module.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

The application of the radioclock module will be recognised automatically

What causes this fault?

This fault occurs when the boiler's main control unit loses its connection to the external radio clock receiver that synchronises the time. The most common reason is a loose wiring connection between the receiver and the boiler, or the internal circuitry of the radio module itself has failed. Because the boiler can no longer confirm the exact time, your programmed heating schedules may become inaccurate.

DIY fix possible

Wait for the boiler to finish its automatic synchronisation processMonitor the display to ensure the code clears and the time updates correctlyRestart the boiler once if the code persists for more than 30 minutes

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