High
Overheat thermostat activated on Halstead Finest 120

Your boiler has automatically shut down because it has detected that its internal water temperature has become dangerously high.

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

Boiler temperature > 105°C • Check CH/O’heat thermistor • Check wires to sensor • Check no air is in CH system • Check PCB • Check pump

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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