High Lockout
AC on Worcester Bosch Greenstar 30HE

Your boiler's main control computer is unable to communicate with its internal plug-in components, meaning the system cannot safely start 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

Module not detected.

What causes this fault?

This fault occurs when the boiler's central brain fails to recognize or connect with the essential control module plugged into it. It is usually caused by a loose internal connection, a sudden electrical surge, or a component failure on the main circuit board that prevents data from flowing correctly.

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

A1View →C6View →

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