High
No code on Worcester Bosch Greenstar Heatslave II

Your boiler has shut down because it is overheating, likely because water is trapped inside it or the pressure is too low to circulate properly.

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

Safety or flow temperature rises too high. Air lock or reduced water content.

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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