Vertiv Liebert DSE Packaged Series Installer/User Manual page 49

4. Accurately weigh in as much of the system charge as possible before starting the unit. Do not exceed the
calculated charge by more than 0.5 lb (0.37 kg).
5. Close the heat-rejection disconnect switch.
• We recommend charging the unit with the return-air setpoint between 75°F and 85°F (24°C and 29°C).
• The return-air temperature to the unit being charged must be stable and must be maintained greater
than 65°F (18°C). If this is not possible due to lack of heat load, then the load banks must be used to offset
the cooling load during start-up. See Table 8.4 below.
6. Close the Liebert®DSE disconnect switch.
7. In the Service menu of the Liebert® iCOM controller, select Diagnostics/Service > Diagnostics.
a. Enable Manual Mode.
NOTE: Manual Mode will timeout after 30 minutes.
b. In Evaporator Fan options, set Motors to ON to operate the fan during Manual Mode.
c. In In Compressor Circuit 1 options, set Compressor Mode to Charge to operate the compressor at full
capacity, energize the blower motor, and open the EEV.
d. Reset the charge function as many times as needed to complete unit charging.
NOTE: You must establish and maintain a minimum of 20 psig (138 KPa) for the compressor to operate.
e. Repeat Step 7 for Compressor Circuit 2.
8. Check the refrigerant level in the refrigerant-level sight glasses on each receiver after the unit has been
operating for at least 15 minutes.
9. Adjust the refrigerant level in each circuit to meet the level shown in Table 8.4 below
10. After adjusting the refrigerant, allow the system to operate for another additional 15 minutes before checking
need of further adjustment.
11. Repeat the procedure for the second circuit.
NOTE: A digital-scroll compressor can have a clear unit sight glass on the liquid line only when operating at 100%
capacity. When operating with a receiver, the unit sight glass might not become clear even when operating at 100%
capacity. When operating below 100%, the unit sight glass may show bubbles with each 15 second unloading cycle.
Table 8.4 Refrigerant Level in Sight Glasses at Outdoor Temperatures
Temperature
40°F (4.5°C) and lower
40°F (4.5°C) and higher
If the return air temperature cannot be maintained between 75°F and 85°F (24°C and 29°C) due to lack of load, then the liquid-level receiver must be
adjusted to the following if return air is between 65°F and 75°F (18°C and 24°C):
40°F (4.5°C) and lower
40°F (4.5°C) and higher
8 Maintenance
Sight Level
Bottom sight glass is 3/4 full
Bottom sight glass is full
Charge to the bottom of the top sight glass.
Top sight glass is 1/4 full
45