BoilerFaultCodes Burner output modulates Low
Boiler Fault Code Burner output modulates
Also written as BURNEROUTPUTMODULATES — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Burner output modulates 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 is automatically adjusting its flame intensity to save energy and balance heat, which is a normal part of its efficient operation rather than a breakdown. (As reported on Alpha CB 240 / 280)
Pick your boiler brand for the Burner output modulates fix
Source
Information for the Burner output modulates 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