Items To Be Checked Before A Test Run - Mitsubishi Electric City Multi PQHY-P72 Service Handbook

VIII Test Run Mode

[1] Items to be checked before a Test Run

1 Check for refrigerant leak and loose cables and connectors.
2 Measure the insulation resistance between the power supply terminal block and the ground with a 500V megger and make
sure it reads at least 1.0Mohm.
Caution:
(1) Do not operate the unit if the insulation resistance is below 1.0Mohm.
(2) Do not apply megger voltage to the terminal block for transmission line. Doing so will damage the controller board.
(3) The insulation resistance between the power supply terminal block and the ground could go down to close to 1Mohm
immediately after installation or when the power is kept off for an extended period of time because of the accumulation
of refrigerant in the compressor.
(4) If insulation resistance reads at least 1Mohm, by turning on the main power and powering the crankcase heater for at
least 12 hours, the refrigerant in the compressor will evaporate and the insulation resistance will go up.
(5) Do not measure the insulation resistance of the terminal block for transmission line for the unit remote controller.
3 Make sure that the stop valve on the gas pipe, liquid pipe, and oil balance pipe are fully open.
Caution: Securely tighten the cap.
4 Check the phase sequence and the voltage of the 3-phase power supply.
Caution: If an open phase or a reverse phase is detected, it will be treated as an abnormal stop during test run (4103
error).
5 Turn on the main power to the unit at least 12 hours before test run to power the crankcase heater.
Caution: Insufficient powering time may result in compressor damage.
6 When a transmission booster is connected to the transmission line for centralized control, be sure to perform a test run with
the transmission booster being powered. Leave the male connector on the female power supply switch connector CN41as
it is (factory setting).
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[ VIII Test Run Mode ]