High
FAIL POINT G Primary Overheat on Worcester Bosch Greenstar Si

Your boiler has detected that it is getting dangerously hot and has shut itself down to prevent damage.

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

Primary Overheat. Boiler not fully water pressurised, air in system, pump failure, primary sensor not correctly fixed, or overheat thermostat short circuit across contacts 5 & 6.

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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