BoilerFaultCodesYour boiler's internal computer chip is no longer being recognised or has malfunctioned, meaning the unit cannot safely control its heating functions.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Replace with new conversion code plug (11). e.g. code plug number 460 or 461
What causes this fault?
This fault occurs when the small memory chip, known as a code plug, becomes loose or develops an internal electrical failure. Without this chip, the boiler's main control board loses its specific 'identity' and forgets the settings required to operate your heating safely. The most common reason is vibrational wear over many years or a power surge that has corrupted the chip's internal data.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like E2 — no call-out fees, no surprises.
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Worcester Bosch Highflow 400 BF is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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