Medium
D.029 on Vaillant ecoTEC Pro 24

Your boiler has detected that the water is not flowing around your heating system fast enough, which often points to a blockage, trapped air, or a struggling pump.

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.

What the manual says

Manufacturer manual

Water circulation vol. actual value

From this model's manual
Verified against the Vaillant Ecotec Pro installation & service manual, page 43.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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