Lockout High

Boiler Fault Code Lockout

Also written as LOCKOUT — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code Lockout appears across 9 boiler brands and 45 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has stopped working because it couldn't successfully light the flame after three attempts, often caused by a temporary interruption in the gas supply or air in the lines. (As reported on Potterton Puma 100e)

Pick your boiler brand for the Lockout fix

Baxi Lockout 3 models Chaffoteaux Lockout 3 models Grant Lockout 6 models Ideal Lockout 2 models Potterton Lockout 11 models Ravenheat Lockout 1 model Saunier Duval Lockout 1 model Vokera Lockout 2 models Worcester Bosch Lockout 16 models

Source

Information for the 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