Low
d.66 on Vaillant ecoFIT Pure 825

Your boiler is simply notifying you that the 'warm start' feature, which keeps water inside the boiler pre-heated for faster taps, has been activated.

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

Activation of the warm start function for hot water

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 31.
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

This is not a fault code, but an information message.If you wish to stop the boiler from keeping water warm, navigate to the menu on your boiler display.Locate the 'Warmstart' or 'Comfort' setting and toggle it to 'Off'.

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