High Lockout
LC9 on Ideal HP290

Your heat pump’s internal power electronics have become too hot and have shut the system down to prevent damage.

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

Inverter High Temperature

What causes this fault?

This fault occurs when the power electronics that drive the heat pump compressor reach a safety temperature limit. It is usually caused by a failure of the internal cooling fan or a build-up of dust and debris blocking the heatsink, preventing the system from shedding heat effectively. When the electronics cannot stay cool, the unit shuts down to prevent permanent component failure.

This fault is more common during summer heatwaves, as high ambient temperatures make it harder for the unit's internal cooling system to keep the electronics within safe limits.

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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