BoilerFaultCodesYour boiler is failing to light because it isn't receiving gas or the ignition system isn't creating a spark.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler goes to lock out | No gas; Isufficient gas; Incorrect gas valve adjustment; Electrode defective; Ignition lead defect; Electronic igniter defective
What causes this fault?
This fault occurs when the boiler attempts to ignite several times but fails to establish a flame, leading the system to shut down for safety. The most common reasons are a lack of gas reaching the unit, a worn-out spark electrode that can no longer light the burner, or a faulty gas valve failing to open. In some cases, it can be caused by something as simple as a recent gas meter exchange or the gas supply being temporarily turned off.
This fault often appears during the first cold snap of winter when components like the gas valve or ignition leads are put under sudden strain after being idle over summer.
DIY fix possible
Check that your gas meter has credit and the isolation valve is openCheck if other gas appliances, like a cooker, are workingPress the reset button (flame symbol with a cross) for one second
Find a Gas Safe engineer
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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like F.28 — no call-out fees, no surprises.
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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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