High Lockout
2963 on Worcester Bosch Greenstar 8000 Life/Style

Your boiler has detected that the sensors monitoring its internal temperature are giving incorrect readings or have failed, causing the system to shut down 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

The heat exchanger sensor or both supply and heat exchanger sensors are defect

What causes this fault?

This fault occurs when the boiler's control board receives conflicting or impossible temperature data from the internal sensors that monitor the main heat exchanger. This usually happens because a sensor has developed an internal electrical fault or the wiring connecting it to the main computer has become loose or corroded. To prevent the unit from overheating, the system shuts down immediately because it can no longer safely track how hot the water is getting.

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

2920View →

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