BoilerFaultCodes 10.3 High
Boiler Fault Code 10.3
Also written as 103 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 10.3 appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has a flame for the pilot light, but the main heating burner is failing to ignite, meaning you won't have any heating or hot water. (As reported on Myson Economist WM)
Pick your boiler brand for the 10.3 fix
Source
Information for the 10.3 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