How much does it cost to fix boiler error code d6?

Typical repair cost for the boiler d6 fault is £150-300 including labour.

d6 Medium

Boiler Fault Code d6

Also written as D6 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code d6 appears across 3 boiler brands and 15 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has lost communication with an external accessory, such as a solar thermal controller or an additional heating control module, which is preventing the system from operating correctly. (As reported on Viessmann Vitodens 242-F B2UA)

Pick your boiler brand for the d6 fix

Alpha d6 9 models Viessmann d6 2 models Worcester Bosch d6 4 models

Source

Information for the d6 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