What is a lineset?

A lineset in a mini-split air conditioning system plays a crucial role in transferring refrigerant between the indoor and outdoor units of the system. The lineset consists of two copper pipes that are typically insulated and bundled together. These pipes are known as the refrigerant lines.

Here’s what each of the pipes in the lineset does:

1. Refrigerant Line (Liquid Line): This is the smaller-diameter pipe and is responsible for carrying liquid refrigerant from the outdoor condenser unit to the indoor evaporator unit. The refrigerant in this line is in a high-pressure, high-temperature liquid state.
2. Refrigerant Line (Suction Line): This is the larger-diameter pipe and is responsible for carrying the low-pressure, low-temperature gaseous refrigerant from the indoor evaporator unit back to the outdoor condenser unit. This pipe allows the refrigerant to complete the cycle, absorbing heat from the indoor space and releasing it outdoors.

The lineset, therefore, facilitates the heat exchange process in the mini-split system. During the cooling cycle, the refrigerant absorbs heat from the indoor air (evaporator) and releases it outside (condenser). During the heating cycle, this process is reversed, with the evaporator unit absorbing heat from the outside air and releasing it inside.

It’s important to properly install and insulate the lineset to ensure the efficient transfer of refrigerant and to maintain the system’s overall performance. The insulation helps prevent heat exchange with the surrounding environment, preserving the temperature and pressure of the refrigerant within the lines.