Low
D.023 on Vaillant ecoTEC plus

Your boiler is currently waiting for a signal from your thermostat or timer to tell it to start heating your home or water.

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

Statusoftheheatdemand

From this model's manual
Verified against the Vaillant Ecotec Plus installation & service manual, page 73.
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 or programmer is set to 'ON' and turned up high enough to trigger the heating.Verify that your heating schedule is active and not currently in an 'OFF' or 'standby' period.Ensure your smart thermostat or internet gateway has a stable connection to your boiler.

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Related fault codes

D.024View →S.00View →

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