Huawei NetCol5000-A035 Quick Manual page 20

Extra Refrigerant Oil Charge
9.2
The refrigerant oil, Danfoss 160SZ, is recommended.
•
If the low-temperature component is not connected, do not add refrigerant oil.
• If the low-temperature component is connected, and L ≤ 10 m, do not add refrigerant oil.
•
If the low-temperature component is connected, and L > 10 m, additional refrigerant oil =
additional refrigerant charge x 4%.
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Leak Checking, Vacuuming, and Precharging Refrigerant
Leak Checking
10.1
Charge 3.5 MPa nitrogen and preserve the system for 24 hours. Provided that 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.
Charging in Refrigerant Oil (Optional) and Vacuuming
10.2
If the low-temperature component is connected and L > 10 m, refrigerant oil is required to add.
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.
Precharging Refrigerant
10.3
1. Take off 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.
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.
4. Open pressure gauge valves, and the refrigerant steel vessel valve to charge refrigerant.
5. Charge 10 kg liquid refrigerant (If low-temperature component is configured, charge 15 kg liquid
refrigerant). The rest refrigerant is to be charged during power-on and commissioning.
6. After refrigerant charging, close pressure gauge valves, and the refrigerant steel vessel valve.
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