Overheat lockout High

Boiler Fault Code Overheat lockout

Also written as OVERHEATLOCKOUT — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code Overheat lockout appears across 4 boiler brands and 15 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 because it has reached too high a temperature, usually due to a lack of water or a blockage in the system. (As reported on Ideal Compact HE)

Pick your boiler brand for the Overheat lockout fix

Baxi Overheat lockout 3 models Ideal Overheat lockout 7 models Johnson Starley Overheat lockout 1 model Potterton Overheat lockout 4 models

Source

Information for the 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 27 April 2026