Low
d.09 on Vaillant ecoFIT Pure 425

Your boiler is simply displaying the target temperature being requested by your external room thermostat or smart control system; this is a status message rather than a breakdown.

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 flow set target temperature that is set on the eBUS room thermostat

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

Check your room thermostat to see if it is calling for heatAdjust your thermostat settings or schedule if the temperature is higher or lower than expectedNo action is required if your heating is performing normally as this is a diagnostic status

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d.00View →d.05View →S.04View →

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