BoilerFaultCodes flashing FILL / HIGH High
Boiler Fault Code flashing FILL / HIGH
Also written as FLASHINGFILLHIGH — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code flashing FILL / HIGH 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's water pressure has dropped too low, which is preventing it from working at its full heating capacity. (As reported on Atag E Range)
Pick your boiler brand for the flashing FILL / HIGH fix
Source
Information for the flashing FILL / HIGH 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