High
Overheat thermostat activated on Halstead Finest Gold

Your boiler has switched itself off because it has become dangerously hot, likely due to a circulation problem or a faulty safety sensor.

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.

What the manual says

Manufacturer manual

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

From this model's manual
Verified against the Halstead Finest Gold installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

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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