Lockout error High

Gledhill Lockout error Fault Code

Also written as LOCKOUTERROR — same fault.

The Gledhill Lockout error fault code means: your boiler has stopped working safely and needs a simple restart to clear a temporary system error.. It appears on 1 Gledhill model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: FLASHING : Lockout error clear by pressing ‘Reset’ button S1
Typical repair cost £0-120 (including labour)

DIY fix possible

Locate the 'Reset' button (labeled S1) on the boiler control panel.Press and hold the Reset button for 2-3 seconds.Wait for the boiler to complete its startup sequence and check if the error light stops flashing.

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Gledhill models that show the Lockout error fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Gledhill Lockout error fault code information on this page is sourced and cross-checked against the official Gledhill service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026