Low
d.08 on Vaillant ecoFIT Pure 835

This is a status code showing whether your external room thermostat is currently asking the boiler to turn the heating on or off.

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

Status of the 230V thermostat (0=Room thermostat open, 1=Room thermostat closed)

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 if your room thermostat is set to a temperature higher than the current room temperature.Ensure the batteries in your wireless thermostat or programmer are working.Verify that the heating 'on' times are correctly set on your timer or app.

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