High Lockout
Boiler sensor on Ideal Concord CXA 40-120

Your boiler has detected an issue with its internal sensors and has stopped running to prevent any damage or incorrect temperature readings.

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

The diagnostics will indicate the nature of the fault to assist a speedy and effective repair

What causes this fault?

This fault occurs when the boiler's internal sensors stop communicating correctly with the main control board. It is usually caused by an electrical failure within the sensor itself or a loose connection in the wiring that prevents the boiler from safely monitoring water temperature. Because the boiler cannot tell how hot the water is getting, it shuts down as a safety precaution.

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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