Medium
d.77 on Vaillant ecoFIT Pure 835

Your boiler is struggling to bring your hot water tank up to the correct temperature, likely due to a sensor issue or a problem with the pump transferring heat to the cylinder.

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

Max. cylinder reheating

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.22View →F.24View →

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