BoilerFaultCodes F.063 High
Boiler Fault Code F.063
Also written as F063 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.063 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's main control computer is experiencing a memory error and can no longer process instructions correctly, meaning the unit will not be able to operate. (As reported on Vaillant ecoTEC Plus 836)
Pick your boiler brand for the F.063 fix
Source
Information for the F.063 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