BoilerFaultCodesYour boiler has detected a flame when there shouldn't be one, which has caused it 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: No demand to gas valve | Electronic board defective; Gas valve defective
What causes this fault?
This fault occurs when the boiler's sensors detect a flame signal even though the gas valve should be closed and no heating is requested. The most common reason is a leaking gas valve allowing fuel to seep through, or a faulty circuit board that is incorrectly interpreting electrical signals as a flame.
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
A boiler cover plan would cover faults like F.27 — no call-out fees, no surprises.
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