BoilerFaultCodes Group 1 High
Boiler Fault Code Group 1
Also written as GROUP1 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Group 1 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 detected a critical internal error that has forced it to shut down to prevent damage, meaning you currently have no heating or hot water. (As reported on Worcester Bosch Greenstar CDi Compact)
Pick your boiler brand for the Group 1 fix
Source
Information for the Group 1 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