BoilerFaultCodes 338 High
Boiler Fault Code 338
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 338 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 repeatedly tried to start but failed to detect water movement, so it has locked itself out to prevent internal damage. (As reported on Worcester Bosch Greenstar CDi Compact)
Pick your boiler brand for the 338 fix
Source
Information for the 338 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