Low
D.023 on Vaillant ecoTEC Pro 30

Your boiler is currently operating in summer mode, meaning it is only set up to provide hot water and has the central heating switched off.

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/winter mode (heating off/on)

From this model's manual
Verified against the Vaillant Ecotec Pro 30 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

Locate the radiator icon or 'Heating' button on your boiler's front control panel.Press the button to toggle the heating mode back to 'On'.Ensure your external room thermostat or programmer is also set to a temperature higher than the current room temperature.

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