Low
d.66 on Vaillant ecoFIT Pure 425

Your boiler is currently pre-heating water so that it is available more quickly when you turn on your hot tap.

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

No action is required as this is a normal status message and not a fault.If you wish to stop this occurring, you can turn off the 'Warm Start' feature in the user settings.Check your user manual for the 'Pre-heat' or 'Comfort' setting toggle.

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