Low
S.31 on Vaillant ecoTEC Plus 826

Your boiler is currently in summer mode, meaning it is working exactly as it should and is simply waiting for you to turn the heating on or call for hot water.

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

Summer mode active or no heat requirement from eBUS controller

From this model's manual
Verified against the Vaillant Ecotec Plus 826 installation & service manual, page 48.
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 boiler display settings to see if the heating mode is set to 'Summer' or 'Off'.Adjust your room thermostat to a higher temperature to see if the boiler begins a heating cycle.Open a hot water tap to confirm the boiler triggers for water heating.

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