DIY 16ft 3/8 x 5/8 Lineset for 24K & 36K Indoor

When a 16 ft Line Set Is the Right Length

Shorter is better on a split system, and most installs end up with more length than the route needs. Every extra foot is pressure drop, more refrigerant in the line and more insulation exposed to weather. At 16 ft this is the shortest MrCool make. It suits a handler on the same wall as the condenser, or one floor above it. Measure the actual route before choosing, including the vertical rise and the slack at both ends, because a line set cannot be shortened. It cannot be lengthened either, except by joining a second set with a coupler kit. This is the 3/8 by 5/8 gauge, which is the pairing for the 24K and 36K air handlers rather than the smaller ones. Both lines come inside a 3/4 in insulation sleeve rated against sun, weather and rodent damage. The set is pre-charged and factory sealed, and the internal seals only open when the fittings are torqued up. MrCool also offer 25 ft, 35 ft and 50 ft in the same gauge. One thing to check first: MrCool changed refrigerant between DIY generations, so match the generation of your unit.

How the Quick Connect Fittings Work, and How They Fail

Quick connect is the reason this can be a two person afternoon rather than a contractor visit. The lines arrive charged and sealed, and the seal inside each fitting breaks only as you torque the nut to specification. That releases refrigerant into a closed loop that was never opened to the air. So no vacuum pump, no manifold gauges, no brazing torch and no refrigerant handling certification. The failures are all mechanical and all avoidable. An under tightened nut does not fail on the day; it weeps and the system loses performance over weeks. An over tightened one deforms the brass flare permanently and cannot be recovered by tightening further. Cross threading a fitting ruins it outright, so start every nut by hand. Hold the fixed side with a backup wrench while you torque, or the whole assembly turns and the seal never sets. Use a torque wrench rather than judgement, because the correct feel is not something anyone learns on one install.

Key Features

• Length: Sixteen feet, the shortest MrCool offer
• Gauge: 3/8 by 5/8, for 24K and 36K air handlers
• Charge: Pre-charged and factory sealed
• How it opens: Internal seals break as the fitting is torqued to spec
• Insulation: A 3/4 in sleeve, rated against sun, weather and rodents
• Not needed: Vacuum pump, gauges, brazing or certification
• Other lengths: 25 ft, 35 ft and 50 ft in the same gauge
• Joining: Two sets can be combined with a coupler kit
• Tools: A torque wrench and a backup wrench
• Check first: The DIY generation of your own unit

Technical Specifications