03 High

Boiler Fault Code 03

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 03 appears across 7 boiler brands and 50 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 problem safely clearing waste gases through the flue pipe, which has caused the system to shut down for safety. (As reported on Vokera Linea Plus AG)

Pick your boiler brand for the 03 fix

Alpha 03 23 models Chaffoteaux 03 6 models Glow-worm 03 2 models Grant 03 1 model Ideal 03 1 model Saunier Duval 03 4 models Vokera 03 13 models

Source

Information for the 03 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 27 April 2026