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

Typical repair cost for the boiler D fault is £120-250 including labour.

D High

Boiler Fault Code D

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code D appears across 3 boiler brands and 4 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has stopped working for safety reasons and is locked out, meaning it needs a manual reset or a professional technician to investigate the internal fault. (As reported on Worcester Bosch 9/14 - 19/24 CBi)

Pick your boiler brand for the D fix

Halstead D 1 model Pro D 1 model Worcester Bosch D 2 models

Source

Information for the D 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