BoilerFaultCodesTechnical description
Fault with mains supply or PCB fuse
What causes this fault?
This fault occurs when the electrical circuit required to wake up the boiler is broken, preventing the control board from receiving power. The most common reason is a blown fuse within the boiler or at the wall switch, often caused by a sudden electrical surge or a faulty internal component like a failing pump or fan. If the fuses are intact, it typically indicates that the main printed circuit board has suffered an electrical failure and can no longer process commands.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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