BoilerFaultCodes ALL 42 Medium
Boiler Fault Code ALL 42
Also written as ALL42 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code ALL 42 appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's control panel is struggling to register your button presses because one of the buttons is stuck or the electronic interface is malfunctioning. (As reported on Sime Murelle Revolution 30)
Pick your boiler brand for the ALL 42 fix
Source
Information for the ALL 42 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