High Lockout
E2 on Worcester Bosch Greenstar CDi Compact

Your boiler has detected a faulty internal temperature sensor, which means it cannot accurately measure how hot the water is and has stopped running 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

Flow sensor short circuit - Flow sensor shorted or damaged.

What causes this fault?

This fault occurs when the boiler's internal thermometer, which monitors the temperature of the water leaving the unit, fails or sends an incorrect signal to the control board. The most common reason is that the sensor has physically degraded over time or suffered an electrical short, meaning the boiler can no longer safely regulate its heat output. In some cases, the issue may also be caused by damaged or loose wiring connecting the sensor to the main computer.

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

E9View →A1View →C6View →

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