BoilerFaultCodes.com
J11 High Lockout

Your heat pump's internal motor system is drawing too much electricity, causing the unit to shut down to protect its electrical components.

Call an engineer soon

Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Inverter High Current

What causes this fault?

This fault occurs when the heat pump's internal electrical system detects a sudden surge or an unsustainably high flow of electricity. It is usually caused by a failing compressor that is struggling to turn or a fault within the electronic control board that manages power distribution. To prevent permanent damage to the wiring, the system automatically shuts down as a safety precaution.

This issue can be more frequent during extreme winter temperatures when the compressor has to work at its maximum intensity for long periods to extract heat from the cold outside air.

Typical repair cost £350-£900 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Protect yourself from future repair bills

A boiler cover plan would cover faults like J11 — no call-out fees, no surprises.

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