BoilerFaultCodesTechnical description
Coding plug not detected.
What causes this fault?
This fault occurs when the small 'identity chip' known as the code plug becomes loose or fails electronically, meaning the boiler can no longer remember which model it is or what its safety settings should be. It is most commonly caused by a physical connection failure at the chip's socket or a breakdown of the internal circuitry on the main control board.
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.
Find a Gas Safe engineer
Search the official register →