Low
S.30 on Vaillant ecoFIT Pure 425

Your boiler is perfectly healthy, but it has received a signal from your wall-mounted thermostat or smart controller to stop heating the house.

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 smart app to ensure the heating is not set to 'Off' or a very low target temperature.Replace the batteries in your room thermostat if it is a wireless model.Increase the temperature setting on your thermostat to see if the boiler resumes operation.

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Related fault codes

S.31View →S.33View →

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