Ductless mini-split install basics

Startup

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Startup· Advanced 4–6 hr

Line-set flaring, evacuation, and startup for a single-zone mini-split.

Tools
Flaring tool (45°) · Torque wrench · Vacuum pump · Micron gauge · Nitrogen
1

Cut, deburr, flare

Use a rigid tube cutter; deburr with tool facing down. Flare using a clutch-type flaring tool.

2

Torque flare nuts

1/4" ~14 ft-lb, 3/8" ~30 ft-lb, 1/2" ~40 ft-lb — verify with unit's IOM.

3

Pressure test with nitrogen

300–500 psig, hold 15 min minimum.

4

Evacuate

Pull to <500 µm; decay test.

5

Release factory charge

Open liquid then suction service valves fully. Add per meter of line-set beyond factory length.

6

Comm wiring

Match S1/S2/S3 by number, not color. Never crimp comm wire into a wire nut with power conductors.

Reference PDFs

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ENERGY STAR
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ENERGY STAR / EPA
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ENERGY STAR / EPA
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ENERGY STAR / EPA
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US Dept. of Energy
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US EPA