Low
S.31 on Vaillant Home System

Your boiler is not broken; it is simply in 'Summer Mode' because the heating is switched off or your thermostat is set lower than the current room temperature.

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

No heating demand: Summer mode, eBUS controller, waiting period

DIY fix possible

Check if your thermostat is set higher than the current room temperature.Ensure the 'Summer Mode' setting on the boiler control panel is turned off.Check your external heating controls or apps to ensure a heating schedule is active.

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Related fault codes

S.0View →S.34View →

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