BoilerFaultCodes Flow Temperature Overheat Lockout High
Boiler Fault Code Flow Temperature Overheat Lockout
Also written as FLOWTEMPERATUREOVERHEATLOCKOUT — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Flow Temperature Overheat Lockout 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 switched itself off to prevent damage because the internal water temperature has become too hot. (As reported on Keston 30C)
Pick your boiler brand for the Flow Temperature Overheat Lockout fix
Source
Information for the Flow Temperature Overheat Lockout 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