How much does it cost to fix boiler error code 406?

Typical repair cost for the boiler 406 fault is £450-£700 including labour.

406 High

Boiler Fault Code 406

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code 406 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's main control computer has developed an internal electrical fault and can no longer manage the heating process safely. (As reported on Viessmann Vitodens 100-W B1GA)

Pick your boiler brand for the 406 fix

Viessmann 406 1 model

Source

Information for the 406 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