Huawei NetCol8000-E220 User Manual page 54

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).
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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Issue 02 (2019-10-10) Copyright © Huawei Technologies Co., Ltd.
(2) Pressure gauge
(4) Low-pressure needle valve
3 Installation Guide
46