Low
d.21 on Vaillant ecoFIT Pure 825

Your boiler is simply indicating whether the 'warm start' feature—which keeps the internal water hot for faster taps—is currently switched on or 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

Status of the warm start for hot water

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 30.
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

Press the 'i' button on your boiler display to view system statusNavigate to the comfort or warm start setting in the menuToggle the setting to your preferred choice of 'On' or 'Off'

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d.20View →d.22View →

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