BoilerFaultCodes 50:1 High
Boiler Fault Code 50:1
Also written as 501 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 50:1 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 has detected a short circuit in the sensor that monitors your hot water temperature, meaning it can no longer accurately heat your tap water. (As reported on Viessmann Vitodens 200)
Pick your boiler brand for the 50:1 fix
Source
Information for the 50:1 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