Medium
F.78 on Vaillant ecoTEC plus Regular

Your boiler has lost communication with the sensor that measures the temperature of your hot water cylinder, which means it cannot tell when the water needs heating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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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

InterruptiontoDHWoutletsensorat externalcontroller | UKlinkboxisconnected,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 →

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