BoilerFaultCodesYour boiler has detected a flame when there shouldn't be one, which has caused the system to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: External light: Gas solenoid valve defective, flame detector defective
What causes this fault?
This fault occurs when the boiler's internal sensors detect a flame after the gas valve has supposedly closed or before the ignition sequence has even started. The most common reason is a sensor that has become covered in carbon deposits and is sending a false reading, or a gas valve that is failing to shut off the fuel supply completely.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F.27 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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