Low
S.30 on Vaillant ecoFIT Pure 835

Your boiler is perfectly fine, but it is currently being told to stay off by your wall-mounted thermostat or heating controller.

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.

What the manual says

Manufacturer manual

Room thermostat is blocking heating mode.

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 33.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check your wall thermostat or heating timer/programmer to ensure it is set to 'On' and the target temperature is higher than the current room temperature.Check if your smart heating system (e.g., Hive or Nest) has a low battery or lost its connection to the boiler.Try temporarily turning the room thermostat up to maximum to see if the boiler activates.

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