BoilerFaultCodesYour boiler has safety-locked itself because it has detected an internal component failure or a communication error between sensors and the control board.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Volatile lockout. Check: Temperature sensor (8000-20,000Ω); Low voltage wiring harness / connections to sensor; Fan / fan harness / connections to fan; Code plug fitted.
What causes this fault?
This fault occurs when the boiler's internal computer loses reliable communication with its safety sensors or the fan. It is often caused by a failing temperature sensor that provides inconsistent readings or a loose electrical connection that prevents the control board from verifying the boiler is operating safely. Essentially, the boiler has shut down because it cannot accurately monitor its own internal heat or airflow.
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 Fast flash (Lockout reset button Off) — no call-out fees, no surprises.
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