High
overheat lock-out state on Worcester Bosch Highflow 400 CDi

Your boiler has switched itself off because it detected that the water inside it has become too hot, likely as a safety precaution.

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

Should the appliance not light, check it is not in the overheat lock-out state, by pressing the re-reset button on bottom right hand side of the control box.

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.

Find a Gas Safe engineer
Search the official register →

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