BoilerFaultCodesYour boiler has tried to start but failed to light the flame, causing it to shut down for safety purposes.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Illuminates if the burner fails to light at the end of the 4 second ignition period; can be reset by pressing the lockout reset button.
What causes this fault?
This fault occurs when the boiler is unable to create or detect a flame during the crucial startup phase. The most common reasons are a lack of gas supply to the unit, a worn ignition spark that cannot light the burner, or a faulty sensor that fails to tell the boiler the flame is safely lit.
DIY fix possible
Check that your gas emergency control valve is in the 'on' position and you have credit if using a prepay meter.Locate the red lockout reset button on the control box at the front of the unit.Press the button once to see if the boiler restarts normally.
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 Lockout warning light — no call-out fees, no surprises.
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Ideal Concord Super Series 4 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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