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Connecting the Refrigerant Pipe
Precautions
Refrigerant pipes can be routed from the bottom or top. Select
the pipe routing based on the actual situation. ![]()
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Before welding, exhaust all nitrogen from the refrigerant pipe to avoid explosion and personal injury.
- When connecting the indoor and outdoor units, you are advised to weld pipes to the outdoor unit first. Seal the pipe after welding if the welding break exceeds 15 minutes to prevent dust and moisture from entering the pipe.
- Before the welding, take measures to protect needle valves (liquid pipe need valve) within 500 mm from the welding position by removing the valve plug or wrapping the valve with a piece of wet cloth.
- Take protective measures, such as spreading a piece of wet cloth, around the welding position, to avoid burning the bottom panel, top panel, side panel, internal components, needle valves, other pipes, thermal insulation foam, power cables, labels, and tags.
- During the welding, avoid exposing the refrigerant pipes for over 15 minutes. Otherwise, system reliability is affected.
- To avoid leakage of ventilation channels and damage to copper pipes, seal the holes after the pipes are routed through the bottom panel. Seal the top of the copper pipes to prevent foreign matter from entering the refrigerant pipes.
- After welding copper pipes that are excessively long or with bends, blow nitrogen into the pipes to clean foreign matter so that other components will not be affected.
- The refrigerant pipe should be wrapped with thermal insulation foam.
- Avoid elbows and ensure that the connection between the indoor and outdoor units is the shortest.
When selecting the refrigerant pipes, note the following:
- Avoid elbows and ensure that the connection between the indoor and outdoor units is the shortest.
- After determining the best pipe route between the indoor and outdoor units, calculate the number of the components that cause local resistance loss, for example, elbows, and convert them into the equivalent length to straight pipes, as shown in Table 3-10.
- The total length of pipes connecting the indoor and outdoor units equals to the equivalent length of the straight pipes plus the length of the straight pipes connecting the indoor and outdoor units.
- You are advised to select the pipes based on the total length of the pipes connecting the indoor and outdoor units, because different pipe diameters influence the voltage drop and performance of the cooling system. For details, see Table 3-11.
- Pipe length mentioned in this document is equivalent.
Table 3-10 Equivalent length of components
Copper Pipe Outer Diameter (in.) |
45° Bend (Unit: m) |
90° Bend (Unit: m) |
180° Bend (Unit: m) |
T-shaped Three-Way Valve |
|---|---|---|---|---|
 |
 |
 |
 |
|
3/8 |
0.12 |
0.2 |
0.4 |
0.6 |
1/2 |
0.14 |
0.25 |
0.5 |
0.65 |
5/8 |
0.17 |
0.3 |
0.6 |
0.7 |
3/4 |
0.2 |
0.35 |
0.7 |
0.8 |
7/8 |
0.24 |
0.42 |
0.8 |
1.2 |
1 |
0.28 |
0.5 |
1 |
1.3 |
1–1/8 |
0.32 |
0.6 |
1.2 |
1.4 |
Table 3-11 Recommended pipe specifications
Pipe Length (m) |
Recommended Gas Pipe Diameter |
Recommended Liquid Pipe Diameter |
|---|---|---|
L ≤ 60 m |
7/8 inch (22.22 mm) |
5/8 inch (15.88 mm) |
60 m < L ≤ 100 m |
7/8 inch (22.22 mm) |
3/4 inch (19.05 mm) |
| If the one-way pipe length is longer than 100 m, contact Huawei technical support. | ||
To dampen noises generated by the equipment due to vibration, refrigerant pipe supports should be installed as required by Figure 3-31.
- When the direction of the refrigerant pipe changes, add a support at the position that is 500 mm away from the changing point.
- If the refrigerant pipe is straight, add a support every 1500 mm.
Onsite personnel are responsible for preparing
the required materials and installing the supports.
Bottom Pipe Routing
- Remove the plugs from the bottom refrigerant pipe using
a welding torque, as shown in Figure 3-32.
- Be careful during welding to avoid burning components, such as rubber rings, inside the cabinet.
- Use a rubber hose to connect the nitrogen cylinder which connecting the reducing valve and the end of the copper pipe, then fill nitrogen at 0.03–0.05 MPa into the copper pipe to avoid internal oxidation, as shown in Figure 3-33.
- When welding a gas pipe, gently inject nitrogen into the pipe through the exhaust pipe needle valve.
- When welding a liquid pipe, gently inject nitrogen into the pipe through the liquid pipe needle valve.
- Cut a cross in the rubber ring using a utility knife and
route the pipe wrapped with the thermal insulation foam through the
hole.
Ensure that the rubber ring is not disconnected. If the rubber ring is disconnected or damaged, seal the gaps around the pipes with mastic cement or thermal insulation foam.
- Connect the gas and liquid pipes to the gas and liquid pipes of the outdoor unit respectively.
Top Pipe Routing
When routing pipes from the top, do not route the pipes over servers or other devices to protect the servers or other devices from being affected by pipe leaks.
- Remove the plugs from the top refrigerant pipe using a welding torque, as shown in Figure 3-34.
- Connect the gas and liquid pipes to the gas and liquid pipes of the outdoor unit respectively. Pipes should be wrapped with thermal insulation foam.
