BoilerFaultCodes Internal error. High
Boiler Fault Code Internal error.
Also written as INTERNALERROR — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Internal error. appears across 1 boiler brand and 4 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has detected an internal computer error, meaning it has safely shut itself down to prevent potential damage to its electronic systems. (As reported on Worcester Bosch Greenstar 25CDi)
Pick your boiler brand for the Internal error. fix
Source
Information for the Internal error. 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