BoilerFaultCodes 308 High
Boiler Fault Code 308
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 308 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 is struggling because there is air trapped inside the pump rather than water, which stops it from circulating heat effectively. (As reported on Worcester Bosch Greenstar CDi Compact)
Pick your boiler brand for the 308 fix
Source
Information for the 308 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