Low
d.43 on Vaillant ecoFIT Pure 435

Your boiler's energy-saving settings for heating your radiators are not correctly configured to match 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

Locate your boiler's digital display and enter the installer settings menuNavigate to setting code d.43Adjust the heating curve value (typically between 1.2 and 1.5) to suit your home's insulation and comfort needs

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d.45View →d.47View →

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