Low
S.0 on Vaillant ecoFIT Pure 435

Your boiler is perfectly healthy and is simply waiting for a signal from your thermostat or timer to start heating your home.

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

Heating mode: No requirement

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 32.
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 thermostat or programmer is set to 'On'Ensure the requested room temperature is higher than the current room temperatureWait for the boiler to automatically trigger when heating is next required

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Related fault codes

S.1View →S.2View →S.3View →

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