Low
d.09 on Vaillant ecoFIT Pure 830

Your boiler is simply displaying the current temperature setting requested by your room thermostat, and there is no fault with the appliance.

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 or smart controller settingsAdjust the desired room temperature if the house feels too hot or coldNo further action is required as this is a status code, not an error

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