09 High

Boiler Fault Code 09

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 09 appears across 10 boiler brands and 49 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected a sequence error or a flame signal where there shouldn't be one, causing the burner to shut down completely for safety. (As reported on Viessmann Vitodens 050-W)

Pick your boiler brand for the 09 fix

Baxi 09 6 models Chaffoteaux 09 5 models Glow-worm 09 7 models Main 09 3 models Potterton 09 3 models Saunier Duval 09 6 models Sime 09 2 models Unical 09 2 models Viessmann 09 2 models Vokera 09 13 models

Source

Information for the 09 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