Low
d.02 on Vaillant ecoFIT Pure 835

Your boiler is taking a short rest to prevent it from switching on and off too frequently, which protects the internal parts and saves energy.

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

Burner anti-cycling time in heating mode

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 that your room thermostat is turned up high enough to call for heat.Ensure at least one or two radiators have their valves (TRVs) turned to maximum to allow heat to circulate.Wait 15-20 minutes for the countdown to end, as the boiler will restart automatically.

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