BoilerFaultCodes DHW PUMP Fast flash High
Boiler Fault Code DHW PUMP Fast flash
Also written as DHWPUMPFASTFLASH — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code DHW PUMP Fast flash appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is having trouble sensing the temperature of your hot water supply, which means it cannot heat your water properly. (As reported on Grant Vortex Eco)
Pick your boiler brand for the DHW PUMP Fast flash fix
Source
Information for the DHW PUMP Fast flash 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