BoilerFaultCodes Tw_Out High
Boiler Fault Code Tw_Out
Also written as TWOUT — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Tw_Out 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 heat pump has stopped working because a sensor that measures the temperature of the water leaving the outdoor unit has failed or is disconnected. (As reported on Ideal HP290)
Pick your boiler brand for the Tw_Out fix
Source
Information for the Tw_Out 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