Medium
d.28 on Vaillant ecoFIT Pure 412

Your boiler's internal control system is having trouble communicating with an external accessory, such as an extra pump or a zone valve.

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

Function of relay 2 (multi-functional module)

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.27View →F.75View →

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