MRCOOL Line set Installation: Left, Right, or Straight Out the Back?

When installing a MRCOOL air handler, you have a few options for routing the refrigerant line set: out the left side, right side, or straight out the back. While both the left and right sides come with pre-scored knockouts to allow for easier modifications, it’s important to understand the potential risks before choosing your routing path.

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Routing the line set out either side can lead to several issues. The most common problem is kinking the line set during installation. The tight space and sharper bends required when exiting from the sides can put unnecessary strain on the copper tubing, increasing the risk of a pinch or collapse in the line. A kinked line set can restrict refrigerant flow, reduce system performance, cause higher operating pressures, and even lead to long-term compressor damage.

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Additionally, when using a side exit, the line set can become more vulnerable to rubbing against sharp edges or being pinched if not properly supported and protected, especially in tight mechanical closets or wall cavities.

Because of these risks, we strongly recommend routing the line set straight out the back of the unit whenever possible. Exiting out the rear provides a much more natural, direct path for the refrigerant lines. It reduces the need for sharp bends, minimizes strain on the tubing, and helps maintain proper refrigerant flow — ensuring better performance and extending the life of your system.

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If you must run the line set out the left or right side, be sure to do the following:

• Locate the molded knockout on the side of the unit. MRCOOL has provided these knockouts specifically to accommodate side routing if necessary.

• Carefully cut along the molded lines using tin snips or a similar tool. Avoid cutting beyond the designated area to maintain the cabinet’s structural strength.

• Protect the line set with grommets, insulation, or protective sleeves as it exits the unit to prevent rubbing or damage from vibration over time.

• Form bends carefully, maintaining a smooth, gentle radius in the copper tubing to avoid kinks.

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In summary, while MRCOOL air handlers are designed with flexibility in mind, straight out the back is the best choice for reliability and longevity. Side exits should only be used when absolutely necessary — and only with careful preparation and attention to detail.