High Lockout
EE8 on Grant Vortex

Your boiler's main control board has lost contact with the digital display or internal computer, meaning it can no longer send or receive instructions.

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 failure

What causes this fault?

This fault occurs when the 'brain' of the boiler and the control panel stop speaking to each other, often due to a loose internal connection or a component failure. It is usually caused by a surge in the electrical supply or moisture affecting the sensitive circuitry inside the casing. Because the two parts cannot sync, the boiler shuts down as a safety precaution because it can no longer monitor its own sensors.

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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