BoilerFaultCodesYour boiler has stopped working because it cannot detect a flame, meaning it has safely shut down to prevent gas from flowing without being burned.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Operation of the flame failure safety device (e.g. main gas inlet cock turned off)
What causes this fault?
This fault occurs when the boiler's control system fails to confirm that a flame has been successfully lit after a sequence of attempts. The most common reasons include a lack of gas reaching the burner, worn-out sparking electrodes that fail to ignite the fuel, or a dirty sensor that can no longer 'see' the flame even if it is actually present.
DIY fix possible
Check that your gas emergency control valve (usually by the meter) is in the 'on' positionCheck if other gas appliances in your home, such as a hob, are working correctlyPress the reset button on the front control panel to see if the boiler restarts
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 Detection Lockout — no call-out fees, no surprises.
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Ideal Concord CXC 48 116 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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