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What is a Line Set Kit?

What is a Line Set Kit?

A line set kit consists of copper tubing and wiring, which connects the indoor and outdoor units, and is required to complete the installation of any Ductless Mini Split system or Unitary Split system. If you’re replacing your old conditioner with a new system, there’s a very high probability that your selected HVAC installation professional will recommend that your existing line sets be replaced. Yes, it may add to your bottom line cost (minimally), but it only makes sense; it's kind of like buying a new car, and telling the dealer to use the battery out of your old car... not a good idea. As much as you would like the installation of your new system to be as straightforward as possible -- and it should be -- some things just 'come with the territory,' and it pays to know a few things about what you’re getting, or what you should rightfully expect. In this case, we’re talking about the Line Set Kit for ductless mini split.
So, What Exactly is a Line Set Kit?
line-setA line set kit is an important piping component of your mini split system. It consists of two copper tubes:
  1. Suction line -- the larger diameter tube connects the evaporator outlet to the compressor inlet.
  2. Liquid line -- the smaller diameter tube connects the condenser to the expansion valve.
To give you a better idea how line sets serve the air conditioning system, it might help to understand how the mini split system works.
In a typical installation configuration, the line sets penetrate through an exterior wall and connect your outdoor condensor unit to the indoor air handler unit. Along these coils, a liquid substance called the refrigerant moves in a cyclic process and constantly changes state—it condenses inside the compressor, and expands / evaporates inside the evaporator. In other words, the specially designed / engineered refrigerant absorbs and releases heat, and in the process produces cool air during an air conditioning operation or warm air when the system is used as a heat pump. The line set is the 'conduit' by which the refrigerant moves between the outdoor unit and the indoor unit. Top quality refrigeration-grade line sets are properly insulated to help maintain maximum integrity of the refrigerant's heat / cool properties between the units, thereby insuring your system gets the full benefit of those properties at the point of delivery into your conditioned space.
  • The suction line transports the refrigerant in its gaseous state, which is basically the cool gas.
  • The liquid line transports the refrigerant in its liquid state, which is basically the warm liquid.
Important Line Sets Sizing Considerations
For the simple reason that they carry refrigerants, the installed line sets can be collectively called the refrigerant piping system. And because the activity of the refrigerant is so vital in the overall operation of an air conditioning system, any incorrect installation of the line sets can be detrimental to the overall stability and reliability of your system. It's important to remember that the size and length of the line sets have to be in perfect unison for the unit and particular type of application during the installation.Simply stated:
  • The SIZE (tubes diameters) of line sets varies according to the type of system.
  • The LENGTH of line sets varies according to specific needs, relative to the installation configuration.
Problems arise when the line sets are either too big or too small.
When line sets are not properly sized, here are some of the main issues of concern:
  • When the suction line is oversized -- the velocity or pressure of the refrigerant will be lower than required to keep the liquid from being carried back to the compressor at optimal efficiently. This would result to the compressor not working properly because the refrigerant helps dissipate heat build-up at the compressor due to friction.
  • When the liquid line is oversized -- a greater amount of refrigerant will be accommodated when it shouldn't be. In this case, the liquid would be easily diluted and the resulting lack of refrigerant can damage the compressor.
  • When the suction line is undersized -- the pressure 'shortage' will affect and thereby reduce the efficiency and capacity of your system, and likely will shorten the system's life time.
  • When the liquid line is undersized -- the evaporator and the condenser of your unit will be starved, which eventually will lower their operating pressures; when this happens, your unit will not properly perform according to its capacity.
So how do I determine which line set kit is right for my application?
We specify the necessary lineset on each product page multiple times. Check the Product Description, as well as the Specifications Tab to easily find the required size lineset. If you need further assistance, use our CHAT option when ordering. Our trained knowledgeable product experts have helped hundreds upon thousands of buyers insure that they acquired exactly the right line set for their installation. Of the many options available in the ComfortUp site, your product specialist most likely will highly recommend the following:
  • JMF Line Sets: Considered the Plug-n-Play option, these are highly durable, pre-flared, and insulated liquid and suction lines that are available in 72 standard combinations. To meet any of your requirements, these line sets are offered in different sizes, types of insulation, and lengths. When it comes to insulation, they come in in either Standard Black Rubber insulation with wall thickness of 1/2" or EZ-PULL® White Polyethylene hard shell insulation with wall thickness of 1/2". As for the length options, you can choose from 15’-75’ - but make sure your length doesn't exceed the "Max Line-Run" length recommended for the system. Check out our selection of JMF line sets to see what fits your needs.
  • Streamline® Line Sets: For more experienced installers, these standard and mini split line sets are made of C12200 grade of copper and available in either an elastomeric or polyethylene insulation which are both UV resistant. You can also check out our great selection of Streamline line sets to find out what suits your requirements.
To summarize... When it comes to ensuring optimal performance and operating efficiency of a new mini split air conditioning system, it's essential to have the right supporting components to maximize that efficiency. The importance of having the correctly sized line set kit is one critical component of the overall system. Refrigerant lines have to be properly sized and correctly installed. To be safe and sure, always follow the manufacturer’s guidelines and seek guidance from your licensed HVAC installer. A line set is required to complete the installation of any mini split system. When replacing your old system, it's unwise to reuse your existing line sets which, over time, may tend to corrode. The smart money investment is a completely new system, stem to stern... including all componentry. It's the right decision.


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