BoilerFaultCodes I.55 Low
Boiler Fault Code I.55
Also written as I55 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code I.55 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 temporarily stopped heating the water because it has reached its maximum safe temperature limit. (As reported on Viessmann Vitodens 100-W WB1A)
Pick your boiler brand for the I.55 fix
Source
Information for the I.55 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