Medium
d.17 on Vaillant ecoFIT Pure 412

Your boiler is reporting a conflict in how it measures water temperature between the pipes, which is preventing it from heating your home properly.

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

Heating control (off=Flow temperature, on=Return temperature)

Engineer required

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

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Related fault codes

d.18View →F.20View →

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