How to install a mini split, from the tech who does it every week.
Step-by-step guides written by [Tech Name], a working HVAC tech who installs ductless systems for a living. Do it yourself with the right steps, or have it done for you.
The install, in the order it happens
Every ductless install follows the same eight steps. Skip one and you find out a few months later.
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1
Pick the spots
Indoor head high on an outside wall, outdoor unit on a level pad with airflow around it. The line set length between them decides a lot.
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2
Mount the bracket
Find the studs, tape up the paper template from the box, and level the plate before the last screw goes in.
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3
Drill the wall
One hole, sloped down toward the outside so condensate drains and rain doesn't come in.
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4
Run the line set
Copper, drain, and communication wire go through together. Gentle bends, no kinks.
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5
Flare and torque
A clean 45° flare and the torque from the manual. This is where most leaks start.
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6
Pressure test
Dry nitrogen to the test pressure in the manual, then soap every joint.
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7
Pull a vacuum
Below 500 microns, then isolate the pump and watch it hold.
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8
Open the valves
Release the charge, cap the valves, and run it in cool and heat.
Guides
Written for homeowners. Nothing here assumes you already own a flaring tool.
- How to install a mini split, start to finish The whole job in the order I do it on a real install, from picking the wall to the first startup. 1 to 2 days on the jobModerate, gauges needed
- How to flare a mini split line set Cut, ream, flare, check, and torque. The connection that causes more callbacks than anything else on a ductless install. 20 to 40 minutes on the jobModerate
- How to vacuum a mini split Pull the line set below 500 microns, prove it holds, then release the charge. Why the micron gauge matters more than the pump. 45 to 90 minutes on the jobModerate
Where DIY usually stops
Plenty of the job is fair game for a handy homeowner. A few parts aren't, either because of the law or because of the warranty.
Most people can handle
- Mounting the wall bracket and indoor unit
- Drilling the wall and running the line set
- Setting the outdoor unit on a pad or wall bracket
- Installing a pre-charged, quick-connect kit per its manual
Get a pro for
- A new 230V circuit and disconnect, unless you're qualified for electrical work
- Opening a sealed refrigerant system or adding refrigerant (EPA 608 certification)
- Flare-type systems whose warranty requires a licensed installer
- Line sets longer than the factory charge covers
Rather have it done right the first time?
[Tech Name] installs mini splits in [City] and about 40 miles around it. Flares torqued to spec, pressure tested, pulled to vacuum, and started up with you watching.