Commissioning; Pre Start-Up - Midea LSBLG MCF Series Technical & Service Manual

Flooded type water cooled screw chiller (MIC)
VI. Commissioning
1.

Pre start-up

(1) Electrical System Inspection
1) Inspect whether power distribution capacity complies with the power of the unit before the first start-up,
and whether the diameter of the selected cable can bear the maximum working current of the master
compressor.
The max economical conveying distance:
The max loading time in a year（h）
<3000 h
3000～5000 h
>5000 h
2) Inspect whether the electricity mode is compliant with that of the unit, three-phase five-line (three
phase lines, one zero line and one earth wire, 380V± 10%).
3) Inspect whether the maximum phase voltage imbalance complies with the requirement, 2% for the
maximum permissible phase voltage imbalance and 5% for the phase current balance. The machine
must not be started up when the phase voltage imbalance exceeds 2%. If the measured imbalance% is
excess, the power supply sector must be notified immediately.
4) Inspect whether the supply circuit for the compressor is firmly and properly connected, and tighten it if
there is any looseness. The screws might be loose due to factors such as long-distance transport and
hoisting of the master compressor. Or, the electrical elements (e.g. air switch, AC contactor, etc.) in the
control cabinet of the master compressor and the compressor might be damaged.
5) Carefully inspect all the electrical lines with a multimeter, and check that all connections are properly
installed. Carry out measurement in mega ohm and ensure that there is no short circuit at the shell.
Inspect whether the earth wire is properly installed, and whether the insulation resistance to ground
exceeds 2MΩ. And inspect whether the supply line meets capacity requirements.
6) Inspect whether the disconnection switch is installed in the supply line of the supply unit.
7) Complete all connections of the main circuit in the control cabinet and all external connections of the
control circuit before power connection (e.g. oil heater, compressor electronic protection, circulatory
water temperature sensor, target-type flow switch connection, water pump linked control, communication
line connection); inspect the bolts of the wiring terminal for looseness. Inspect whether various electric
meters and appliances are properly installed, complete and available. Inspect the interior and exterior of
the electrical cabinet, especially various wiring ports, for cleanness. If the communication lines of the
PCB and control screen are damaged, refer to the diagram below.
8) After the inspection for all the above items is completed, connect the control cabinet and the supply
indication lamp will light up, indicating that the oil heater is working. Observe whether the phase loss
protection is normal, if it is (green light on), close the single-pole switch in the control cabinet, then the
control circuit will begin working, and the touch screen and PCB control will be put into operation.
Copper core length(m)
264
294
331
82
MCAC-CTSM-2018-1