High Lockout
E46 on Keston C36

Your boiler's main control panel has lost connection with the internal computer that runs it, meaning the boiler cannot receive commands.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Flue sensor open circuit - check connections to flue sensor are in place

What causes this fault?

This fault occurs when the data link between the boiler's display screen and the main internal computer is broken or interrupted. The most common reason is a loose or damaged wiring connection inside the casing, though it can also be caused by moisture affecting the delicate electronic circuit boards.

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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Related fault codes

E01View →E02View →E40View →

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