Precharging Refrigerant - Huawei NetCol8000-E220 User Manual

NetCol8000-E220 Modular Indirect Evaporative
Cooling System
User Manual
Figure 3-30 Vacuumizing
(1) Vacuum pump
(3) Liquid pipe needle valve
Step 2 In the beginning, the vacuum pump makes loud noise and exhausts white smoke
from the exhaust vent. After 10 minutes, if it still exhausts white smoke, observe it
for another 10 minutes because the cooling system may not be sealed properly or
there may be too much refrigerant or water residues in the cooling system.
Step 3 After 20 minutes, the pressure gauge pointer should be in the negative area and
the vacuum pump makes small noise. Close and open the pressure gauge
alternatively for several times. The position of the pressure gauge pointer and the
sound made by the vacuum pump do not obviously change. Otherwise, the
cooling system may not be sealed properly.
Step 4 Vacuumize the cooling system for at least 80 minutes after checking that the
cooling system does not leak. The pressure displayed on the vacuum pump should
be less than or equal to 60 Pa (absolute pressure). When the pressure stops
dropping, pump for another 10 minutes. The indication of sight glass is dry
(green).
Step 5 Close all the pressure gauge valves, and the vacuum pump after vacuumizing the
cooling system. Preserve the pressure for 10 minutes without disconnecting the
connection. The pressure should be lower than and equal to 90 Pa (absolute
pressure).
----End

3.11 Precharging Refrigerant

Issue 06 (2020-08-19)
NO TE
If the precision of the pressure gauge is too low to display 60 Pa (absolute pressure), ensure
that the pressure gauge pointer stays at the minimum scale while vacuumizing the cooling
system. Preserve the pressure for 1 hour, and make sure the displayed pressure does not
increase obviously.
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(2) Pressure gauge
(4) Low-pressure needle valve
3 Installation Guide
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