High Lockout
L5E on Ideal HP290

Your heat pump’s main engine is struggling to pull enough power to start up correctly.

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

Compressor Start Error

What causes this fault?

This fault occurs when the heat pump's compressor tries to turn on but cannot reach its required operating speed. It is usually caused by an electrical component failing to provide the initial 'push' needed to start the motor, or a blockage preventing the internal parts from moving freely.

This issue is more frequent during the first cold snap of autumn, as components that have sat idle during the summer may struggle to restart under increased demand.

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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