Low
S.31 on Vaillant ecoTEC plus aquaPLUS

Your boiler is currently set to summer mode, which means it will provide hot water but has been told not to turn on the central heating.

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 (heating control knob in off position)

From this model's manual
Verified against the Vaillant Ecotec Plus Aquaplus installation & service manual, page 38.
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

Locate the central heating control knob (the one with the radiator symbol) on the boiler's front panel.Turn the knob clockwise away from the 'off' or sun icon position to your desired temperature setting.Ensure your room thermostat or external heating controls are also calling for heat.

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