BoilerFaultCodesYour boiler has stopped working and locked itself to prevent damage, requiring you to identify the specific number following the L code to find the exact fault.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler is in lockout for a specific error. Display will show a number after the 'L' to indicate which error is detected.
What causes this fault?
This fault occurs when the boiler's internal computer detects a critical failure and shuts the system down to ensure safety. The most common reasons involve a failure in the ignition process, such as a worn-out spark electrode or a faulty gas valve preventing fuel from reaching the burner.
DIY fix possible
Check the display for the number shown after the L (e.g., L2)Hold the reset button for two secondsIf the boiler does not restart after one reset attempt, call a Gas Safe engineer
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like L — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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