BoilerFaultCodesYour boiler has failed a safety check during its start-up sequence because it cannot identify the gas type or verify the flame correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Gas family check unsuccessful
What causes this fault?
This fault occurs when the boiler's internal computer tries to verify the quality and type of gas entering the system but fails to receive a stable reading. It is physically caused by a mismatch between the gas valve's output and the detection signal from the ignition probes, often due to a components failing to regulate the fuel flow correctly. The most common reason is a malfunctioning gas valve or a faulty control board that can no longer process the flame signal.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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