BoilerFaultCodes 2964 B High
Boiler Fault Code 2964 B
Also written as 2964B — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 2964 B appears across 1 boiler brand and 3 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 that water isn't moving through the main heating unit quickly enough, often caused by a blockage or a pump issue. (As reported on Worcester Bosch Greenstar 30i)
Pick your boiler brand for the 2964 B fix
Source
Information for the 2964 B 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