Liebert PX018 Installer's/User's Manual page 41

6. Turn on the Liebert PDX/PCW disconnect switch, and operate the unit for 30 minutes using
the charging function for each circuit of the system.
• You must operate the indoor fan using the "Diagnostic" menu of the Liebert iCOM control.
• 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 and energizes the liquid-
line solenoid valve. The reheat and humidifier are disabled.
• The charging function can be reset as many times as required to complete unit charging.
7. Attach pressure and temperature instruments to the liquid-line of the indoor unit, measure the
initial subcooling, and continue to add charge until the recommended subcooling for the
current outdoor ambient temperature is reached. See Table 5.9 below. Read the outdoor
ambient temperature from the Liebert MC condenser control menu ID F02.
NOTE: To determine subcooling measurement, you must measure the liquid-line pressure reading (at
the factory-installed Schrader tap) and obtain a temperature reading on the liquid line. Convert the
liquid-line pressure reading into a liquid temperature using a Pressure-Temperature Guide or Table 5.10
on the next page. Subtract the measured temperature from the saturated-liquid temperature. The
difference is subcooling. Make sure to use the saturated liquid temperature to calculate subcooling.
8. As head pressure builds, the variable-fan-speed controlled condenser fan begins rotating. The
fan will run at full speed when sufficient head pressure is developed.
Vertiv | Liebert® PDX™ and PCW™ Installer/User Guide |
Table 5.9 Target subcooling
for ambient outdoor temperature
Ambient Temp, °F (°C) Subcooling, °F (°C)
0 (-17.8)
10 (-12.2)
20 (-6.7)
30 (-1.1)
40 (4.4)
50 (10.0)
60 (15.6)
70 (21.1)
80 (26.7)
90 (32.2)
95 (35.0)
100 (37.8)
105 (40.6)
110 (43.3)
125 (51.7)
DPN002411, Rev. 8
22 (12.0)
22 (12.0)
22 (12.0)
22 (12.0)
22 (12.0)
21 (11.7)
19 (10.8)
17 (9.3)
13 (7.2)
9 (5.0)
7 (3.9)
5 (2.9)
3 (1.8)
1 (0.7)
0
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