BoilerFaultCodesPotterton Lockout (Red LED) Fault Code
Also written as LOCKOUTREDLED — same fault.
The Potterton Lockout (Red LED) fault code means: your boiler has stopped trying to light itself because the small starter flame failed to ignite within the safety time limit.. It appears on 1 Potterton model in our database.
Technical description: The pilot will attempt to light, if the pilot does not light within 60 seconds (due to air in the system) the boiler controls will go to 'Lockout' and the LED on the user controls will go Red.
What causes the Potterton Lockout (Red LED) fault?
This fault occurs when the boiler's internal safety system detects that the small pilot flame hasn't lit correctly. The most common reasons are a build-up of debris on the ignition part or air trapped in the gas supply, which prevents the spark from catching. If the boiler cannot confirm a healthy flame within 60 seconds, it shuts down to prevent unburnt gas from escaping.
This issue is more frequent during the autumn when a boiler is turned back on after months of inactivity, as air or debris can settle in the pilot assembly during the summer.
DIY fix possible
Locate the reset button or turn the control knob to the 'Reset' position.Hold for 5 seconds and release.If the fault persists after three attempts, contact a Gas Safe engineer to clear air from the gas line.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Potterton models that show the Lockout (Red LED) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton Lockout (Red LED) 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 27 April 2026