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Technical Information
2. IPM Protection, Out-of-step Fault, Compressor Phase Overcurrent (AP1 below refers to the outdoor
control panel)
Main check points:
• Is the connection between control panel AP1 and compressor COMP secure? Is the connection in
correct order?
• Is the voltage input of the machine within normal range? (Use AC voltmeter to measure the voltage
between terminal L and N on wiring board XT)
• Is the compressor coil resistance normal? Is the insulation of compressor coil against the copper tube
in good condition?
• Is the working load of the machine too high? Is the radiation good?
• Is the charge volume of refrigerant correct?
Fault diagnosis process:
