BURNER FIRING 100% Low

Boiler Fault Code BURNER FIRING 100%

Also written as BURNERFIRING100 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code BURNER FIRING 100% 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 is currently operating at its highest power setting to meet a high demand for heat or hot water, and this is a normal status message rather than a fault. (As reported on Grant Spira)

Pick your boiler brand for the BURNER FIRING 100% fix

Grant BURNER FIRING 100% 1 model

Source

Information for the BURNER FIRING 100% 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