High
Heat exchanger overheat on Worcester Bosch Greenstar 12i System

Your boiler has detected that parts inside are getting dangerously hot and has automatically switched itself off to prevent permanent damage or a safety hazard.

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

Fault indication / Lockout reset button

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

EAView →CEView →E9View →

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