Low
Vitotronic 300 on Viessmann Vitorond 100

Your heating system has switched to a special winter operating mode because it has detected freezing temperatures outside.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Activates after 0°C / 32°F outdoor temperature

DIY fix possible

Check that the outdoor temperature sensor is not covered by snow or iceMonitor the heating display to ensure the radiators are warming up as expectedVerify that the 'Frost Protection' setting on the Vitotronic control unit is set to your preferred comfort level

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