High
CH flow sensor fault on Worcester Bosch Greenstar i

Your boiler's temperature sensor is struggling to communicate with the main control board, which is preventing your heating from operating correctly.

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

CH flow sensor (8000 - 20000 ohms at room temperature). Wiring and connections to sensor.

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 →EAView →

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