Licensed work
Refrigerant, vacuum, and dedicated electrical work belong with a licensed HVAC pro. Homeowner planning stops at mounting and the line set.
How-to
Mini Split Line Set Length
Classic AmericaNov 4th 20264 min read
The short answer
- Precharge is the line length the factory refrigerant charge covers. On our single-zone spec sheets, that's 25 ft.
- The maximum run is 50 ft on the 9,000 BTU sheet, 65 ft on the 23,000 BTU sheet, 49 ft on the 17 SEER2 12,000 BTU sheet, and 131 ft on DUET.
- The included line set is 16 ft on the 9,000, both 12,000 BTU models, and the 23,000 BTU model. DUET includes 2 x 16 ft.
- If your run goes past the maximum, you'll need a different layout, not a longer homemade line.
Precharge, included length, and the maximum
Mini split line set length really means three different measurements, and mixing them up is how installs get ordered wrong. The included length is the copper in the box. The precharge length is how far the factory refrigerant charge is meant to reach. The maximum length is the longest run the manufacturer rates. Beyond the precharge, a technician may need to add refrigerant following the manual. Beyond the maximum, the system is outside its rating. You won't find an ounces-per-foot recipe here, since that adjustment is licensed HVAC work from the installation manual.
| Model | In the box | Precharge | Maximum | Pipes |
|---|---|---|---|---|
| 9,000 BTU | Not listed | 25 ft | 50 ft | 3/8 in gas · 1/4 in liquid |
| 12,000 · 19 SEER2 | 16 ft | 25 ft | 50 ft | 3/8 in · 1/4 in |
| 12,000 · 17 SEER2 | Not listed | 25 ft | 49 ft | 3/8 in · 1/4 in |
| 23,000 BTU | Not listed | 25 ft | 65 ft | 1/2 in gas · 1/4 in liquid |
| DUET | Two runs; feet not one listed kit length | 49 ft | 131 ft | 3/8 in · 1/4 in, each head |
From the spec sheet
- 12,000 BTU/h cooling · 1 ton
- 19 SEER2
- 115V
- Up to 550 sq ft
- Heating nameplate 12,200 BTU/h
From the spec sheet
- 18,000 BTU/h cooling · 1.5 tons
- 24 SEER2, non-ducted
- 208/230V
- Two 9,000 BTU indoor heads on one outdoor unit
- Heating nameplate 20,000 BTU/h
Measure the path, not the straight-line distance
The line set follows the wall: down from the head, through the sleeve, along the outside, and into the condenser, with gentle bends along the way. A 12 ft walk from the head to the condenser can turn into an 18 ft copper path once you add the drop and the service loop. Enter that path in the Install Planner. If it's under the included length, the kit has you covered. If it falls between the included length and the maximum, order a longer set with the **same diameters** before the crew shows up. Heads up: the 23,000 BTU gas line is 1/2 inch, not the 3/8 inch used on the smaller heads, so don't reuse a smaller set.
DUET is two lengths
Each DUET indoor head has its own line set running back to the outdoor unit, so check both. One short run to a bedroom and one long run to a far-off office can put just the second line near the 131 ft maximum. Each line is precharged for 25 ft, the same as the single-zone sheets, so still check the second run.
Length mistakes you can't DIY your way out of
- Please don't flare on extra copper yourself to “make it reach.” Connections, added refrigerant, and the vacuum are jobs for a licensed HVAC pro.
- Don't go past the maximum. Move the outdoor unit or pick a different wall instead.
- Don't assume every box includes 16 ft. Only the models in the table list that.
- You're covered for 5 years on the compressor and 1 year on parts. Classic America strongly recommends a licensed HVAC install and may refuse the warranty if the unit wasn't professionally installed.
Put the feet on the bid
If you haven't settled on a capacity yet, figure it out in the Size Finder before you commit to a wall. Write both the included length and your measured path into the install scope, since labor changes with a long run. Check out mini split AC installation cost to see how that shows up in published ranges (which aren't our prices), and what’s in the box for everything else on the pallet.
FAQ
Common questions
How long can a mini split line set be?
The maximum run is 50 ft on the 9,000 BTU and 19 SEER2 12,000 sheets, 49 ft on the 17 SEER2 12,000, and 65 ft on the 23,000 BTU sheet. DUET’s maximum is 131 ft. Just stay within the number for the model you buy.
What does precharge length mean?
It's the line length the factory refrigerant charge is meant to cover. Our single-zone sheets say 25 ft, and DUET says 25 ft per line. A longer run, within the allowed maximum, may need refrigerant added by a licensed technician. We don't give a charge amount here.
Is the line set included?
Yes, a line set ships in the box. The included length is 16 ft on the 9,000, both 12,000 BTU models, and the 23,000 BTU model. DUET includes 2 x 16 ft.
Can I use a longer line set than the maximum?
No. Change the layout so the run fits, since going past the maximum puts the system outside its rating.
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