BoilerFaultCodes 374 8C High
Boiler Fault Code 374 8C
Also written as 3748C — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 374 8C appears across 1 boiler brand and 2 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 repeated issues with maintaining its flame during operation, so it has locked itself for safety to ensure it does not attempt to fire incorrectly. (As reported on Worcester Bosch Greenstar CDi Compact)
Pick your boiler brand for the 374 8C fix
Source
Information for the 374 8C 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