BoilerFaultCodesYour boiler's internal computer has failed a self-test and is no longer able to communicate with the rest of the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fault: Main PCB self-test failed. Main PCB defective
What causes this fault?
This fault occurs when the boiler's central control board fails its internal safety checks during startup or operation. The most common reason is a hardware malfunction within the circuitry, often caused by a component reaching the end of its lifespan or suffering damage from an electrical power surge. Because the board can no longer safely manage the gas and ignition process, it shuts the system down to prevent any hazards.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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