High Lockout
EH258 on Worcester Bosch GB162

Your boiler's computer brain has developed a serious internal fault or a loose connection, preventing it from starting the burner safely.

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

The burner control unit is faulty – check the plug and wiring of the burner control unit.

What causes this fault?

This fault occurs when the boiler's internal computer can no longer communicate reliably with the components that manage the gas flame. The most common reason is an electrical failure within the control board's circuitry or a communication break caused by a loose or damaged wiring connection. Because the boiler cannot guarantee it can control the fire safely, it shuts down entirely as a protective measure.

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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