Low
Vitotronic 300 on Viessmann Vitopend 100

Your boiler's outdoor temperature sensor has detected freezing conditions and is telling your heating system to run continuously to prevent your pipes from freezing.

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 sensor is not covered by snow or iceMonitor the heating system to ensure radiators are getting warm as expectedNo action is typically required as this is an automatic frost protection feature

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