High Lockout
E83 on Main Eco Compact

Your boiler's internal computer parts are having trouble talking to each other, which means the system has stopped working for safety.

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

Communication error

What causes this fault?

This fault occurs when the boiler's internal control board loses touch with the display panel or the smart sensors inside the unit. It is usually caused by a loose connection in the wiring or a tiny electrical component failing due to age and heat. Because the brain of the boiler can no longer see what the rest of the components are doing, it shuts down as a safety precaution.

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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