BoilerFaultCodesYour boiler has gone into a safety lockdown because it cannot confirm that internal components like the fan or temperature sensors are working correctly.
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. Possible solution/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 main control board loses communication with vital safety components like the fan or temperature sensors. It is usually caused by a loose wire, a faulty sensor that is sending incorrect readings, or a fan motor that has failed to start. Without these components working perfectly, the boiler shuts down immediately to prevent any risk of overheating or unsafe operation.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like Blue light: Fast flash, Lockout reset button: Off — no call-out fees, no surprises.
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