High
F.49 on Vaillant ecoFIT Pure 830

Your boiler is having trouble communicating with its external controls, likely due to a loose wire or a problem with the connection between your thermostat and the boiler.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

eBUS low voltage

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.49View →

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