Mastering the Excess: A Comprehensive Guide on Handling Mini-Split Line Set Surplus

When dealing with excess line set on a mini-split system, it is crucial to handle it correctly to ensure optimal performance and longevity. Coiling the line set is not recommended, as it can lead to issues with oil flow and potential refrigerant leaks. Instead, consider the following expert-level techniques to manage the surplus line set effectively.

Shortening the Line Set: A Precise Approach

If possible, reducing the length of the line set to the minimum required for your installation is the most efficient solution. This process involves cutting and reflaring the lines, which requires precision and skill. Before attempting to reflare the actual lines, it is essential to practice making flares on scrap copper to ensure you have the necessary technique.

When cutting and reflaring the line set, consider the following steps:

  1. Measure and Mark: Carefully measure the required length of the line set and mark the excess portion to be cut.
  2. Cutting the Copper Tubing: Use a tubing cutter or a fine-toothed hacksaw to make a clean, square cut on the copper tubing. Ensure that the cut is perpendicular to the tubing’s axis to maintain the integrity of the flare.
  3. Deburring and Cleaning: After cutting, use a deburring tool or fine-grit sandpaper to remove any burrs or sharp edges from the cut end of the tubing. Thoroughly clean the tubing with a lint-free cloth to remove any debris or contaminants.
  4. Flaring the Tubing: Invest in a quality flaring tool and follow the manufacturer’s instructions to create a proper flare on the cut end of the tubing. Ensure that the flare is uniform and free of any cracks or imperfections.
  5. Leak Testing: Before reassembling the system, perform a thorough leak test using a leak detector or a bubble solution. This step is crucial to ensure the integrity of the new flare and prevent any potential refrigerant leaks.

It is important to note that shortening the line set might affect the system’s refrigerant charge, so you may need to adjust it accordingly. Refer to the system’s documentation to determine the precharged refrigerant amount and try to match the total line set length as closely as possible to avoid refrigerant charge issues.

Hiding the Excess Line Set: Concealing the Surplus

what to do with excess line set on mini splitImage source: Flickr

If shortening the line set is not feasible, you can hide the excess by building a box or enclosure around the condenser unit. This not only conceals the extra lines but also provides protection for the unit. When designing the enclosure, consider the following factors:

  1. Dimensions: Measure the excess line set and determine the appropriate size of the enclosure to accommodate it comfortably, allowing for some additional space for airflow and maintenance access.
  2. Material Selection: Choose a durable and weather-resistant material, such as wood, metal, or a composite, to construct the enclosure. Ensure that the material can withstand the outdoor elements and provide adequate protection for the condenser unit.
  3. Ventilation: Incorporate ventilation openings or louvers in the enclosure design to allow for proper airflow around the condenser unit. This will prevent overheating and ensure efficient operation.
  4. Accessibility: Design the enclosure with removable panels or hinged doors to allow easy access for maintenance and servicing of the condenser unit.
  5. Aesthetic Considerations: If desired, you can incorporate decorative elements or blend the enclosure with the surrounding landscape to enhance the overall visual appeal of the installation.

By building a well-designed enclosure, you can effectively conceal the excess line set while protecting the condenser unit and maintaining the system’s performance.

Managing the Excess Line Set: Laying It Flat

If hiding the line set is not an option, it is crucial to ensure that the excess is laid flat and not coiled. Coiling the line set can lead to issues with oil flow and potential refrigerant leaks, which can compromise the system’s efficiency and longevity.

When managing the excess line set, consider the following best practices:

  1. Lay the Excess Flat: Carefully uncoil the excess line set and lay it flat on the ground or secure it to the wall or floor using appropriate fasteners. Avoid creating any low spots or loops in the line set, as these can trap oil and impede proper refrigerant flow.
  2. Insulate the Line Set: Ensure that the entire line set, including the excess portion, is properly insulated to prevent heat transfer and condensation buildup. Use high-quality insulation materials designed for HVAC applications.
  3. Protect the Line Set: Secure the line set to the wall or floor using clamps or brackets to prevent it from being damaged or disturbed. This will also help maintain the flat layout and prevent the formation of low spots.
  4. Monitor for Changes: Regularly inspect the excess line set to ensure that it remains flat and undisturbed. If any changes or issues are observed, address them promptly to maintain the system’s optimal performance.

By following these guidelines, you can effectively manage the excess line set and avoid the potential issues associated with coiling or improper handling.


Dealing with excess line set on a mini-split system requires a careful and methodical approach to ensure the system’s long-term performance and efficiency. Whether you choose to shorten the line set, hide the excess, or manage it through a flat layout, it is essential to follow the proper techniques and best practices to achieve the desired results.

Remember, attention to detail and adherence to the manufacturer’s recommendations are crucial when working with HVAC systems. By mastering the techniques outlined in this comprehensive guide, you can confidently tackle the challenge of excess line set and maintain the optimal operation of your mini-split system.


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