Low
d.31 on Vaillant ecoFIT Pure 435

Your boiler is displaying a configuration setting rather than a fault, indicating how the system is set to top up its water pressure.

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

Automatic filling device (0=Manual, 1=Semi-automatic, 2=Automatic)

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 'Menu' button on the displayUse the arrow keys to navigate through the diagnostic codes to reach 'd.31'Check if the setting matches your preferred filling method (Manual, Semi-auto, or Automatic)

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