Nobu NBL4-09IDU32 Service Manual page 53

Service Manual
(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? Loose? 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 the
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:
Installation and Maintenance
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Service Manual
Installation and Maintenance
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