BoilerFaultCodes 6F:100 Medium
Boiler Fault Code 6F:100
Also written as 6F100 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 6F:100 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 telling you that it has defaulted to its maximum power setting for heating your hot water because it has encountered a configuration memory error. (As reported on Viessmann Vitodens 200)
Pick your boiler brand for the 6F:100 fix
Source
Information for the 6F:100 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