Application

Air-conditioning branch pipes are used in VRV air-conditioning systems to connect the main unit with multiple terminal units (evaporators). They are divided into gas pipes and liquid pipes, with the gas pipe generally having a larger diameter than the liquid pipe.

After passing through the expansion valve or capillary tube for throttling, the refrigerant flows out from the main unit outlet and enters the liquid pipe of the branch joint. The refrigerant is then distributed through the liquid pipe to other branch joints and terminal evaporators. After absorbing heat in the evaporators and becoming gas, the refrigerant returns to the compressor of the main unit through the gas pipe.

Multi-split system branch joints are used to connect several indoor units in series. The selection of branch joints is determined according to the capacity of the indoor units connected downstream of each branch joint.

Air-conditioning branch pipes can be installed horizontally or vertically:

• For horizontal installation, the angle between the branch outlet and the horizontal line must be less than 15°.
• For vertical installation, when facing the two branch outlets, the angle between either outlet and the vertical line must be less than 15°.
• The piping after the two branch outlets must have a straight pipe length of more than 600 mm.
• A small branch pipe must not replace a large branch pipe.

The inlet and outlet of the branch pipe are composed of multi-section copper pipes with different diameters, which increases flexibility in model selection.

Branch pipes are manufactured by processing and welding purple copper tubes, and their selection is extremely important.

Currently, VRV central air-conditioning systems mainly use R410A refrigerant. This refrigerant is more environmentally friendly and has better cooling performance than traditional refrigerants, but it also operates at a much higher pressure.

If the branch pipe is not selected properly, it may cause leakage or pipe bursting after installation, resulting in significant losses to the VRV air-conditioning system and creating unnecessary trouble.

Selection Standards

1.Check the copper pipe material and surface appearance:

a.The quality of the copper pipe directly determines the quality of the branch pipe. Currently, VRV central air-conditioning systems mainly use R410A refrigerant, which operates under higher pressure. Therefore, branch pipes must be manufactured using copper pipes specially designed for R410A. This type of copper pipe has higher density, more advanced manufacturing processes, and higher pressure resistance than ordinary copper pipes.

b.Branch pipes made from ordinary TP2 copper pipes may show surface peeling, cracking, or striped/net-like patterns, indicating that the crystal structure of the copper material has been seriously damaged during processing. Selecting branch pipes with such defects will create serious hidden risks for the entire piping system.

2.Check the thickness of the branch pipe:

The thicker the pipe, the higher the pressure it can withstand. Therefore, thickness should be one of the first factors to consider when selecting a branch pipe.

3.Check the welding joints:

All branch outlets are formed by welding, and welding points are the most likely areas for problems. Common welding defects include sand holes, incomplete welding (cold joints), and internal oxide inclusions. A high-quality branch pipe should have smooth and clean inner and outer pipe walls, with welding joints that are clear, bright, and free of impurities.

Advantages

1.Exclusive customized brazing materials: RVG uses its own specially customized welding materials, professional silver brazing technology, and internal cavity auxiliary welding, further improving product reliability.

2.Optimized design for easy installation and cost control: The optimized shape and length make installation easier while helping to control costs. The thickness at the three-way junction is specially increased, and the flow channels of both copper and brass three-way joints are optimized to reduce resistance, ensure proper flow rate, and guarantee smooth and balanced refrigerant distribution.

3.Strict pressure testing for every unit: Dedicated branch pipe testing equipment and special testing fixtures are used for each model. Every gas pipe and liquid pipe branch unit undergoes a 6.5 MPa pressure test before leaving the factory.

4.Fast customized solutions: Personalized customization can be quickly provided according to the user’s required pipe diameter and product shape for actual installation needs.

5.Flexible connection accessories: Various reducer connectors and related fittings can be supplied based on the user’s installation requirements.

6.Standard insulation kit available: Optional branch pipe insulation kits are provided, fully complying with the national standard GB20286-2006.

Specification

RVG-YJ-Y Series Table Universal VRF Refnet Joints

RVG-YJ-U Series Table Universal VRF Refnet Joints

Related Products

Thermostat

Pressure Controller

Evaporator / Condenser Air Coils

Vibration Absorber