Low
d.01 on Vaillant ecoFIT Pure 425

Your boiler is simply finishing its normal cooling down cycle after a period of heating, which is a standard operational state and not a fault.

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

Pump overrun in heating mode

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 29.
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 status code, not an error.Wait for the pump symbol to disappear once the system has cooled down.If the code never disappears, contact a professional to check the pump settings.

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