BoilerFaultCodesYour boiler has tried to fire up five times without success and has shut itself down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: If, after 5 attempts the burner has failed to light, the boiler will go to lockout and L-01 will be displayed on the screen.
What causes this fault?
This fault occurs when the boiler cannot detect a flame after several attempts to start. The issue is typically caused by a lack of gas reaching the burner, a faulty ignition system failing to create a spark, or a dirty sensor that cannot confirm the fire is actually lit.
This fault is more frequent during the first cold snap of autumn when internal components or gas valves may stick after being dormant throughout the summer.
DIY fix possible
Check if other gas appliances (like a hob) are working to confirm gas supplyEnsure your gas meter has credit if you use a prepay meterPress the 'Reset' button on the control panel to try and clear the lockout
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
A boiler cover plan would cover faults like L-01 — no call-out fees, no surprises.
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Ideal Concord CXA 40-120 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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