BoilerFaultCodes ALL01 High
Boiler Fault Code ALL01
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code ALL01 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 has failed to ignite, which means it cannot provide any heating or hot water until it is reset or repaired. (As reported on Sime iQE Simplicity 20T)
Pick your boiler brand for the ALL01 fix
Source
Information for the ALL01 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