Medium
D.016 on Vaillant ecoTEC plus

Your boiler is struggling to receive the signal from your wall-mounted thermostat to turn on the heating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Roomthermostatstatus(24V)

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 if the batteries in your room thermostat need replacing.Ensure your thermostat is switched on and showing a signal icon.Turn the thermostat temperature up higher than the current room temperature to see if the boiler responds.

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Related fault codes

F.76View →D.017View →

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