Huawei NetCol8000-A045D Quick Manual page 36

9
Leak Checking, Vacuuming, and Precharging Refrigerant
9.1 Leak Checking
Charge 3.0 MPa nitrogen and preserve the system for 24 hours. If the ambient temperatures
before and after the preservation are similar, the system pressure should not drop. If leaks
occur after the preservation, check them along the pipe, especially at the welding positions,
needle valve, and angle valve.
9.2
Vacuuming
The vacuuming time should be 80 minutes at least and the final pressure (absolute pressure)
should be 60 Pa at most. When the pressure stops dropping, pump for another 10 minutes.
After the vacuumization, close all the vacuum pump and valves. Preserve the system for
another 10 minutes and the pressure (absolute pressure) should be 90 Pa at most. If the
pressure gauge cannot be precise at 60 Pa, ensure that the pressure is displayed at the
minimum scale. Extend the preservation time to one hour. Then check whether the pressure
displayed on the pressure gauge increases.
9.3
Precharging Refrigerant
If the R410A refrigerant is provided by Huawei, put the refrigerant steel vessel upside down
when charging in the refrigerant. If the refrigerant is not provided by Huawei, check with the
refrigerant provider whether the steel vessel has a siphon. If the vessel has a siphon, put it
upside up when charging in refrigerant. If the vessel has no siphon, put it upside down when
charging in refrigerant. These measures ensure that the refrigerant is charged in the liquid form.
1. Remove the vacuum pump from the vacuuming equipment, and replace the vacuum pump
with a refrigerant steel vessel.
2. Partially open the refrigerant steel vessel valve and rubber tube nut. Tighten the nut when
you feel cold air coming out from the nut.
3. Put the refrigerant steel vessel upside down on an electric balance. Clear the reading on the
balance.
4. Open pressure gauge valves, and the refrigerant steel vessel valve to charge refrigerant.
5. The amount of refrigerant charged must be more than half of the total charge amount
calculated and less than the total charge amount. Charge the remaining refrigerant during
power-on commissioning.
6. After refrigerant charging, close pressure gauge valves, and the refrigerant steel vessel valve.
If one NetCol8000-A090D is used with two NetCol500-A060s (or one NetCol500-A120) and the
L is 80 m, the 9.4 + (80 – 10) x 0.28 = 29 kg needs to be filled in each compressor system. In
total, the NetCol8000-A090D needs charging of 58 kg R410A refrigerant.
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