Medium Warning
D.13 on Vaillant ecoTEC plus Regular

There is a communication problem with the pump that circulates hot water, which usually means your hot water or heating might not work as expected.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

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

Hot water circulation pump

What causes this fault?

This fault occurs when the boiler's main control board loses touch with the pump responsible for moving hot water around your system. The most common reason is an electrical failure within the pump's internal circuitry or a loose connection in the wiring that prevents the pump from receiving instructions.

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.27View →

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