BoilerFaultCodesYour boiler has failed to ignite or lost its flame and has shut down as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: LOCKOUT
What causes this fault?
This fault occurs when the boiler tries to light but fails to detect a stable flame after several attempts. The most common reasons are a lack of gas supply to the appliance, a worn-out ignition spark, or a faulty sensor that cannot 'see' the flame even if it has lit.
This fault is more common during extreme cold snaps, as freezing temperatures can cause the external condensate pipe to block, preventing the boiler from completing its ignition cycle.
DIY fix possible
Check that your gas pre-payment meter (if applicable) has credit.Ensure the gas isolation valve under the boiler is in the 'on' position.Press the 'Reset' button on the front of the boiler display for 2 seconds.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
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