Medium
13 on Vaillant ecoTEC exclusive

Your boiler has lost communication with its wall-mounted thermostat, meaning it doesn't know when to switch your heating on.

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

Bus connection (digital room thermostat/control)

From this model's manual
Verified against the Vaillant Ecotec Exclusive installation & service manual.
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

Turn off the electrical power to your boiler for 60 secondsTurn the power back on and wait for the system to rebootCheck all cables between the boiler and your wall thermostat for loose connections or damage

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