LG line set sizes
The right line set diameter for your LG mini-split by capacity — across the Art Cool and standard wall-mounts — plus the length limits and the one thing that changed recently: LG's current units run R-32. Prefer to size by run length too? Use the size calculator.
LG line set size by capacity
Line set diameter is set by your system's capacity. Match your LG unit's BTU rating to the typical liquid-and-suction pair below — sizes shift between LG's R-410A and R-32 generations, so confirm against your manual.
| LG system size | Typical line set (liquid × suction) |
|---|---|
| 9,000 BTU | 1/4" × 3/8" |
| 12,000 BTU | 1/4" × 3/8" |
| 18,000 BTU | 1/4" × 3/8" or 3/8" × 5/8" (by config) |
| 24,000 BTU | 1/4" × 1/2" to 1/4" × 5/8" (by generation) |
| 36,000 BTU | 3/8" × 5/8" |
These cover LG's common single-zone wall-mounts. A couple of LG quirks: the 24,000 BTU suction line changed between the older LS240HEV (5/8") and the LS240HEV2 (1/2") revisions, and the 18,000 BTU can be specified in two pipe configurations depending on the run length. Always confirm the exact diameters against your model's manual before buying.
LG runs R-32 on current units — match your line set, tools, and charge
LG's current single-zone wall-mount lineup uses R-32 refrigerant, while older HSV5, HEV, and Art Cool HYV units use R-410A. The copper line set itself is the same regardless of refrigerant, but your vacuum pump, gauges, and any field charge must match your unit's refrigerant. LG units also ship with a dry holding charge, not refrigerant, so you flare, pull a vacuum, then release the factory charge from the outdoor unit.
Field-flared, not quick-connect
LG mini-splits use standard field-flared line sets with a 45-degree SAE flare, not pre-charged quick-connect. You flare the copper ends and pull a vacuum before opening the service valves — work that typically needs a vacuum pump and EPA 608 certification. Shop standard line sets for an LG install, or see pre-charged line sets if you want the no-vacuum route on a compatible system.
LG line set length limits
Diameter is only half the spec. Your LG system also limits how long the line set can run and how far the indoor and outdoor units can sit apart in height, and those limits depend on the generation. Plan your run to the figures below, then confirm the exact limits for your model in its installation manual.
| Minimum line length | Maximum line length | Max vertical separation | Pre-charged for |
|---|---|---|---|
| 9.8 ft (3 m) | 66–164 ft by capacity | 33–98 ft by generation | 16–41 ft by capacity |
LG's limits move with capacity and generation. The 9,000–12,000 BTU units allow about 82 ft of line with up to 49 ft of vertical separation, an 18,000 BTU reaches about 115 ft, and a 24,000 BTU about 66 ft. LG's newer R-32 extended-piping units stretch the 24,000–36,000 BTU range to about 164 ft with up to 98 ft of lift. The factory charge covers roughly the first 16–41 ft depending on capacity; beyond that an HVAC pro adds about 0.16–0.22 oz per foot. LG lists a minimum run of about 9.8 ft.
How to find your LG model's line set size
- Identify the model and generation. Note the model number — an HSV5, HEV, or HYV prefix is R-410A, while a KSUAB, KSSAP, KUSAC, or KNSAP prefix is the newer R-32 line.
- Check the installation or engineering manual. It lists the exact liquid and suction diameters, the maximum line length, the vertical lift, the pre-charge distance, and the refrigerant for your model — the final word.
Common questions
What size line set does an LG 12,000 BTU use?
Most LG 12,000 BTU single-zone units use a 1/4" liquid line with a 3/8" suction line, the same pair as the 9,000 BTU models. Larger units step up. Confirm against your model's installation manual.
What refrigerant do LG mini-splits use?
LG's current single-zone wall-mount lineup uses R-32 refrigerant; older HSV5, HEV, and Art Cool HYV units use R-410A. The copper line set is the same either way, but your tools, gauges, and any added charge must match your unit's refrigerant.
What is the minimum line set length for an LG mini-split?
LG specifies a minimum line set length of about 9.8 feet (3 m) to limit noise and vibration. Keep your run at or above that and confirm the figure in your model's manual.
What is the maximum line set length for an LG mini-split?
It depends on capacity and generation. LG's 9,000–12,000 BTU units allow about 82 ft, an 18,000 BTU up to about 115 ft, and a 24,000 BTU about 66 ft; the newer R-32 extended-piping 24,000–36,000 BTU units reach up to 164 ft, with 49–98 ft of vertical separation. The factory charge covers roughly the first 16–41 ft; beyond that an HVAC pro adds refrigerant. Confirm your unit's maximum in its manual.
This page provides general guidance on LG mini-split line set sizing based on published LG specifications. Exact line diameters vary by series and model, and lengths, maximum line length, vertical lift, and refrigerant (R-410A or R-32) differ by unit — always verify against your unit's official installation manual before purchasing or installing.