BoilerFaultCodesPotterton Lockout Fault Code
Also written as LOCKOUT — same fault.
The Potterton Lockout fault code means: 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.. It appears on 10 Potterton models in our database.
Technical description: Boiler fails to light within 3 attempts (due to air in the system). Upper Red LED on the control panel will go to a rapid flashing mode.
DIY fix possible
Check that your gas supply is turned on at the meter and that other gas appliances are workingLocate the reset button or turn the control knob to the reset position to clear the errorWait for the boiler to cycle through its ignition process automatically
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Potterton models that show the Lockout fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton Lockout fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026