F63 High

Boiler Fault Code F63

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F63 appears across 2 boiler brands and 8 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's internal computer has encountered a critical memory error and can no longer safely control the heating system, requiring professional attention. (As reported on Heatline Capriz Plus)

Pick your boiler brand for the F63 fix

Glow-worm F63 1 model Heatline F63 7 models

Source

Information for the F63 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