Medium
F.78 on Vaillant ecoTEC plus System

Your boiler is having trouble communicating with the external controls meant to manage your hot water cylinder.

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.

Technical description

InterruptiontoDHWoutletsensoratexternalcontroller Linkboxconnected,buthotwaterNTCnotbridged

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.77View →F.76View →

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