Vertiv Liebert DSE - Page 42

6. Close the unit disconnect switch, and operate the unit for 30 minutes using the charging
function for System#1 and System#2 in the "Diagnostic" menu of the Liebert® iCOM controller.
• A minimum 20psig (138kPa) must be established and maintained for the compressor to
operate.
• The charging function operates the compressor at full capacity, energizes the blower
motor, and opens the EEV.
• The charging function can be reset as many times as required to complete unit charging.
7. Check the refrigerant level in the refrigerant-level sight glasses on each receiver after the unit
has been operating for at least 15minutes.
NOTE: Each receiver at the condenser has 2 sight glasses and the refrigerant level varies with outside
temperature.
8. Adjust the refrigerant level in each circuit to meet the level shown in Refrigerant-level Sight
Glasses ontheReceiver below.
9. After adjusting the refrigerant, allow the system to operate an additional 15minutes before
checking the for the need of further adjustment.
NOTE: A digital-scroll compressor can have a clear sight glass only when operating at 100% capacity.
When operating with a receiver, the sight glass might not become clear even when operating at 100%
capacity. When operating below 100%, the sight glass may show bubbles with each 15-second
unloading cycle.
Refrigerant-level Sight Glasses ontheReceiver
On the receiver(s) at the condenser are 2refrigerant-level sight glasses. Refrigerant level will vary with
outside temperature and return-air temperature at the indoor unit. Check refrigerant level after the unit
has been on for at least 15 minutes and the return-air temperature is stable between 75°F and 85°F (24°C
and 29°C). Make any adjustments to the refrigerant charge to achieve the following levels.
Sight Glass Levels at Outdoor Temperatures
• 40°F (4.5°C) and lower—bottom sight glass is 3/4 full
• 40°F (4.5°C) and higher—bottom sight glass is full
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—Charge to the bottom of the top sight glass.
• 40°F (4.5°C) and higher—top sight glass is 1/4 full
Vertiv | Liebert® DSE™ Installer/User Guide
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