Low
d.43 on Vaillant ecoFIT Pure 425

Your boiler is confused because it is receiving conflicting instructions regarding how hot the radiators should be based on the outside temperature.

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

Heating curve

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

Navigate to the installer menu or settings on your external heating control (like a vRC 700 or sensoHOME).Identify the 'Heating Curve' setting.Adjust the curve value to a standard setting (typically 1.2 to 1.5) to clear the software conflict.

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F.22View →d.47View →

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