High Lockout
EC256 on Worcester Bosch GB162

Your boiler's computer system has detected an internal electronic fault, preventing the heating and hot water from starting up.

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 has an error

What causes this fault?

This fault occurs when the boiler's internal computer can no longer communicate correctly with the parts that manage the flame. The most common reason is an electronic failure within the control board or a loose connection in the internal wiring. This prevents the boiler from safely starting the ignition process, so it shuts down to protect the system.

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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