BoilerFaultCodes HW light flashing High
Boiler Fault Code HW light flashing
Also written as HWLIGHTFLASHING — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code HW light flashing 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 detected an electrical fault with the sensor that monitors your hot water temperature, meaning it cannot heat water safely. (As reported on Ideal Classic FF)
Pick your boiler brand for the HW light flashing fix
Source
Information for the HW light flashing 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