Low
S.31 on Vaillant Turbomax Plus 828 E

Your boiler is perfectly fine; it is simply set to 'summer mode' which means it will provide hot water when you turn on a tap, but will not heat your radiators.

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 Turbomax Plus 824 828e 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 radiator temperature dial on the front of the boiler control panel.Turn the dial clockwise to your desired temperature setting.The boiler will automatically switch from 'summer mode' to normal operation.

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