Huawei NetCol5000-A021HN12D 20020E1 Quick Manual page 22

10
Calculating the Amount of Refrigerant and Refrigerant Oil
1. The recommended refrigerant oil is RL® 32-3MAF/emkarate or RL32H/emkarate. You can
purchase it from Huawei, or purchase it by yourself after being confirmed by Huawei.
2. One-way pipe length = Straight pipe equivalent length + Length of straight pipes between
indoor and outdoor units. The maximum one-way pipe length should be 80 m for NetCol500-
A026 If the requirements cannot be met, contact Huawei technical support.
Type
One-way pipe length (m) 0 < L ≤ 10
Refrigerant charging
amount (kg)
Refrigerant oil charging
amount (kg)
11
Leak Checking, Vacuumizing, and Precharging Refrigerant
Leak Checking
11.1
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.
Vacuumizing
11.2
The vacuumizing time should be 80 minutes at least and the final pressure (absolute pressure) should
be 60 Pa at most. When the final pressure does not decrease more, continue to vacuumize for 10
minutes. After vacuumizing is complete, close the vacuum pump and all valves, and preserve the
pressure for 10 minutes. Ensure that the absolute pressure does not exceed 90 Pa. If the minimum
reading of the pressure gauge is greater than 60 Pa, ensure that the pointer stays at the smallest
scale of the pressure gauge and preserve the pressure for 1 hour. Then check that the pressure does
not rise.
Precharging Refrigerant
11.3
1. Close the high-pressure valve and low-pressure valve of the pressure gauge.
2. Take off the vacuum pump from the vacuumizing equipment, and replace the vacuum pump with
a refrigerant steel vessel.
3. Partially open the refrigerant steel vessel valve and rubber tube nut. Tighten the nut when you
feel cold air coming out from the nut.
4. Put the refrigerant steel vessel upside down on an electric balance. Clear the reading on the
balance.
5. Open pressure gauge valves, and the refrigerant steel vessel valve to charge refrigerant.
6. Refrigerant to be partially charged should be no less than half of total calculated amount, and no
more than the total calculated amount. (Charge less than 1 kg of refrigerant from the low
pressure side, and charge the rest from the discharge pipe needle valve.)
7. After refrigerant charging, close pressure gauge valves, and the refrigerant steel vessel valve.
NetCol500-A026
10 < L ≤ 80
9 + (L – 10) x
9
0.19
0 0
21
Equivalent Length of Pipe
Components
Copper 90-
Pipe Outer degree
Diameter Bend
3/4 inch 0.35 m
5/8 inch 0.3 m
180-
degree
Bend
0.8 m
0.6 m