Vertiv Liebert XDC, User Manual

Page: 44 / 70

System Startup and Commissioning 37
4.2. MCB Position
The positions of the main isolation switch and MCB of the dual system unit are shown in Figure 3-2 , distinguish them
according to the label instructions on the actual cabinet.
4.3. Static Refrigerant Charge
After the vacuuming is completed, the refrigerant can be charged statically:
1. Ensure that the air switches of compressor 1 and compressor 2 of the unit are disconnected to prevent the starting of the
compressor by mistake.
2. Power on the unit and all terminals at the same time, and keep them in ready state.
3. Ensure that the unit enters the vacuum mode.
4. Ensure that the position of the schrader valve for static refrigerant charging is at schrader valve 3, as shown in
Figure 2-6 .
5. Carry out static refrigerant charge for #1 and #2 systems respectively.
6. Until the refrigerant cannot be charged into the system, the static charging ends.
Note: The hose connected to the composite pressure gauge must be vented.
Note: Ensure to charge the refrigerant statically at the required position, and avoid static charge of the refrigerant at the
compressor suction port.
Note: In the process of static refrigerant charging, if the unit exceeds the vacuum mode, user must ensure that the
system enters the vacuum mode again through the settings.
Note: The longer on-site connecting pipe, the greater the requirement for static charging.
Note: After the static charging is finished, ensure that the compressor crankcase heating belt is preheated for more than
12 hours before starting up, or use a dryer to heat the lower part of the compressor shell for about 30minutes.
4.4. Dynamic Refrigerant Charging
After completing the static charging of refrigerant, and after preheating the compressor as required, dynamic refrigerant
charging can be performed:
1. Close the compressor MCB to make the unit enter the running state.
2. The position of the schrader valve for dynamic refrigerant charging is at schrader valve 4, as shown in
Figure 2-6.
3. Perform dynamic refrigerant charging for #1 and #2 systems respectively
4. After the unit is stably operating, ensure that the sight glasses of the #1 and #2 systems are free of bubbles, and the
subcooling in front of the valve reaches above 6 °C.
5. After the operation is stable, ensure that the exhaust superheat of the unit is within the range of 25 °C to 40 °C .
6. If there is no problem with the above commissioning, the whole unit debugging is completed.
Note: The hose connected to the composite pressure gauge must be vented.
Note: After the dynamic refrigerant charging is completed, the subcooling in front of the valve must be ensured,
otherwise the system may run abnormally.