BoilerFaultCodesYour boiler has detected a critical internal fault and has locked itself out to prevent damage or unsafe operation.
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 (sensor, fan or code plug): Temperature sensor (8000 - 20000Ω); Wiring/connections to sensor; Fan/cable/connections; Code plug fitted.
What causes this fault?
This fault occurs when the boiler's internal computer detects a conflict or failure in its safety sensors or the fan that clears exhaust gases. The most common reason is that a sensor has stopped reporting the correct temperature or the fan is no longer spinning at the required speed, causing the system to shut down for safety. Since the boiler cannot confirm the system is venting or cooling correctly, it locks itself out to prevent overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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