BoilerFaultCodesYour boiler is failing to light the burner correctly, meaning it cannot heat your home or water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Burner does not fully ignite / 230V at pin 3 of terminal X15 (Right white wire) or pin 2 of terminal X15 (Left white wire)
What causes this fault?
This fault occurs when the boiler's control system attempts to start the heating process but fails to detect a sustained flame. The most common reason is that the gas valve isn't opening correctly to deliver fuel, or the ignition system is failing to provide the spark needed to light the burner. As a safety precaution, the boiler stops trying to fire to prevent unburned gas from building up.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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
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