How much does it cost to fix boiler error code D.17?

Typical repair cost for the boiler D.17 fault is £90-180 including labour.

D.17 Low

Boiler Fault Code D.17

Also written as D17 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code D.17 appears across 3 boiler brands and 31 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has switched its control method to the return pipe because it is detecting a potential issue with the main flow sensor. (As reported on Vaillant ecoTEC)

Pick your boiler brand for the D.17 fix

Glow-worm D.17 6 models Heatline D.17 6 models Vaillant D.17 19 models

Source

Information for the D.17 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026