Medium
d.16 on Vaillant ecoFIT Pure 825

Your boiler is currently reporting that the signal from your wall-mounted thermostat is not being detected, which means it doesn't know whether to turn your heating on or off.

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

Status of the 24V 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 that your wall thermostat has fresh batteries installed.Ensure the thermostat is switched on and displaying a signal icon.Turn the boiler off at the fused spur for one minute and back on to reset the connection.

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