High
Overheat thermostat on Halstead Ace

Your boiler has automatically turned itself off because it got too hot, likely to prevent internal damage or overheating.

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

The appliance is fitted with an overheat thermostat. If the boiler overheats, the 'lockout' (red LED) will illuminate. This requires manual resetting of the thermostat button located behind the front casing.

From this model's manual
Verified against the Halstead Ace 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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