The Catalog · Line Sets
Mini Split Line Sets.
Pre-Charged. No Vacuum.
The line set is the pair of insulated copper tubes that connect the outdoor condenser to the indoor air handler — one liquid line, one suction line. MrCool DIY systems ship with pre-charged Quick Connect line sets, so you don\'t need a vacuum pump or refrigerant scale. We also stock no-vac extensions, replacement line sets, and standard flare-fitting line sets for pro installs.
In Stock · Ships to All 50 States
In-Stock Line Sets
50' R-454B No-Vac Lineset
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50ft 1/4 x 1/2 Lineset for DIY 9K, 12K & 18K Indoor w/ DIY Pro Cable - R454B
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25ft 1/4 x 1/2 Lineset for DIY 9K, 12K & 18K Indoor
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16ft 3/8 x 5/8 Lineset for DIY 24K & 36K Indoor
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16ft 1/4 x 3/8 Lineset for DIY 6K, 9K & 12K Indoor - R454B
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35ft 1/4 x 3/8 Lineset for DIY 6K, 9K & 12K Indoor w/ DIY Pro Cable - R454B
Ships nationwide·In stock
16ft 1/4 x 1/2 Lineset for DIY 9K, 12K & 18K Indoor - R454B
Ships nationwide·In stock
25ft 3/8 x 5/8 Lineset for DIY 24K & 36K Indoor w/ DIY Pro Cable - R454B
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16FT 1/4" x 1/2" MRCOOL MC16-1412 Flared Line Set Kit for 12K and 18K Mini Split
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50ft 3/8 x 5/8 Lineset for DIY 24K & 36K Indoor w/ DIY Pro Cable - R454B
Ships nationwide·In stock
35ft 1/4 x 1/2 Lineset for DIY 9K, 12K & 18K Indoor w/ DIY Pro Cable - R454B
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GeoCool No-Vac Vertical Upflow w/o Air Box 3/8 3/4 Prechg. Lineset
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Buying Guide
How to choose the right line set
The line set is the most overlooked part of a mini split install — but the wrong one means leaks, voided warranties, and lost refrigerant. Here's what to know.
Length: measure twice, buy once
Line sets come in 15ft, 25ft, 35ft, and 50ft. Measure the actual route from outdoor condenser to indoor unit including bends and vertical rises — add 10% margin. You can't splice line sets in the field; if you're short, you have to buy a longer one and coil the excess. Pre-charged Quick Connect line sets are non-cuttable.
Pre-charged Quick Connect (DIY) vs flare fitting (pro)
MrCool DIY pre-charged line sets have factory-installed Quick Connect fittings — hand-tighten, no vacuum pump, no flare tool. Pro line sets have field-flared ends — require a flare tool and a vacuum pump. Pre-charged is the only option for true DIY install; flare fittings are the standard for pro installs.
Refrigerant compatibility
R-410A line sets work with R-410A systems. R-454B line sets (5th Generation) work with R-454B systems. They're NOT interchangeable — using an R-410A line set on R-454B equipment can cause refrigerant cross-contamination and void the warranty. Match your line set to your equipment refrigerant.
No-vac extensions
No-vac extensions add length to existing pre-charged line sets without breaking the refrigerant seal. Useful when your install distance exceeds the longest available factory length, or when you need to reroute a system. They use the same Quick Connect technology as the original line set.
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Frequently Asked
Common questions
How long can a mini split line set be?+
Most MrCool systems support up to 50 feet of line set length and 25 feet of vertical rise. Beyond that, the system loses efficiency and may require additional refrigerant charge. For very long runs, consult the manufacturer specs for your specific model.
Can I cut a pre-charged line set to length?+
No. Pre-charged Quick Connect line sets are factory-sealed with refrigerant inside — cutting them releases the refrigerant and ruins the system. Order the closest length up from your measurement and coil the excess in a wide loop near the outdoor unit.
Do I need a vacuum pump for a DIY mini split?+
No — that's the whole point of pre-charged Quick Connect line sets. The line set arrives with the right amount of refrigerant already inside, and the Quick Connect fittings hand-tighten in seconds. No vacuum pump, no manifold gauges, no flaring tool.
Can I reuse an old line set on a new mini split?+
Generally no. Refrigerant residue from the old system can contaminate the new one, especially when switching from R-410A to R-454B. Best practice is fresh line set for new equipment. The exception: same-refrigerant replacement of just an outdoor unit, where the existing line set can sometimes be flushed and reused (consult a pro).