Medium
D.12 on Vaillant Combi Compact 242EB

Your boiler is having trouble communicating with the pump that provides and stores your hot water.

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

Cylinder charging pump via accessory 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.10View →D.13View →

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