BoilerFaultCodes 701 Medium
Boiler Fault Code 701
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 701 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 detected a fault with the heating zone 1 flow temperature sensor, which means it cannot accurately monitor the water temperature leaving the boiler. (As reported on Ariston Alteas One)
Pick your boiler brand for the 701 fix
Source
Information for the 701 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