BoilerFaultCodes 4E High
Boiler Fault Code 4E
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 4E 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's temperature sensors have detected an internal conflict or failure, meaning the system can no longer safely monitor how hot the water is getting. (As reported on Buderus 600-28C)
Pick your boiler brand for the 4E fix
Source
Information for the 4E 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