Check the isolation of the motor windings. Should be in the mage-ohms (you need an isolation tester / high voltage ohm meter for this). Check the voltage when the compressor is running. If the voltage drop significantly when the compressor starts/runs, you have a bad connection somewhere.
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[pdf] When pressing “Enter” the following interface will pop up and the password will be required (9999). NOTE: Customer Password can be modified in the CUSTOMER PARAMETER menu. Page 23 KRSD series ENTER PASSWORD ****. Page 24 UNLOAD P. *.**Mpa Unload pressure setting.
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