Mini Split Install - Tools, equipment needed?

jshillin · May 4, 2026

I've been contemplating a mini split install in my insulated 24x32 garage for quite some time and I think I'm ready to pull the trigger. Part of the reason is it would be great to have and another part is that I really want to install one...

I'm looking at an 18000 BTU Costway, R32, 21 SEER2 & 9 HSPF. Along with that, I plan on ordering the outside wall mount and the slimline cover kit. I ran a sub panel to my garage years ago and I made sure to leave plenty of room to add a 220 line for the mini split.

I know I need an outside disconnect and some 10 Gauge wire and a breaker for the panel.

For tools, I already bought a VP6D Pro-Set Vacuum Pump, 2 Stage, 6cfm and a set of hoses. I have torque wrenches, everything to cut the hole, run the lines, etc.
Other than the following, what am I missing?
Nitrogen Tank and regulator
Manifold Gauges compatible with R32. I was looking at the EliteTech digital's for the price and ease of use.
I keep reading that a Micron gauge isn't required, but a good idea to actually see if the vacuum holds.
Do I need a 5/16-inch vacuum-rated Valve Core Removal Tool ?

I'm looking for some advice and anything that you think I could use or don't need. I want to install one at my house because I know my parents will need one soon and want to get this one installed at my house first.

Any help is greatly appreciated!

- Jason

dcg9381 · May 4, 2026

jshillin said:
I keep reading that a Micron gauge isn't required, but a good idea to actually see if the vacuum holds.

If you're going to pressure test with nitrogen, I don't think you need to see if it holds a vacuum, someone can correct me. I borrowed a buddy's nitrogen tank, don't have a need for one myself.

I didn't remove any valve cores.

Most HVACs require some sort of disconnect near the compressor and may require an "accessory outlet" 120V for code.

You may need a "crows foot" for your torque wrench to torque the lines down.

American Locomotive · May 4, 2026

The pressure test is what checks for leaks. If it can hold 400-500 PSI for 24 hours without moving, it's probably good. The vacuum pump is a necessary part of system installation to remove any moisture and non-condensables from the system. The better the vacuum you achieve, the longer and happier your system will run.

The micron gauge is an essential part of doing a "good job" with a minisplit, IMO. You don't need a core removal tool, but it makes the vacuum process so much faster and is a convenient places to hook up your hoses and gauges. If you do get one, you will absolutely need a vacuum rated core-removal tool - go get the "good one" from Appion. The cheap one from Amazon will drive you nuts - ask me how I know.

If you have a TIG welder, or know someone that does, you can use argon in place of nitrogen to purge the system and pressure test so you don't have to buy a bottle. A nitrogen regulator will screw right on to an argon bottle.

todd_fuller · May 5, 2026

I recently did my mini split, a Daikin R32 Atmophera. I did a lot of reading before buying tools. I wasn't in a rush to get it commissioned so I allowed myself to maybe not have everything ahead of time. This is the list of tools I used:

- 5/16" core removal tool (mini split is different from normal AC units + the end fitting is 1/4 so you can use normal AC hoses with it)
- 1/4" AC hose for nitrogen purge/pressure test
- nitrogen regulator
- vacuum pump + new vacuum oil (new oil is real important to getting deep vacuum. I bought a used pump and with old oil it wasn't capable of pulling below 500microns, with new oil I got the system to 120 microns)
- vacuum gauge (I got an Elitech full-range version, ended up buying a BluVac micron gauge because it had a nice vacuum leak rate detector that worked over several hours. Elitech would have worked just fine, getting the vacuum right is really important and it isn't as simple as turn on vacuum until it's a small number, at that vacuum, even gas in the hose values makes a difference and it's meaningful to see the vacuum vs time curve)
- (vacuum hoses - optional, but makes vacuuming it out a lot faster. They are bigger)
- flaring tool (mine didn't have a lineset and I needed to cut to length, make sure it's an 'orbital' flaring tool. My factory flares weren't that pretty either)
- tubing bender (I got a cheap-o ratchet one and it was OK. I also got these internal Easybend benders which go inside the copper to prevent a kink when you hand bend)

A note about second-hand vacuum gauges. I read a lot about gauges and seems that most of them can get ruined by oil contaminants. Some have are more resistant or clean easily and some have replaceable parts, but buying used means it could give bad readings.

The supplies you may need extra are the condensate line (sometimes they are a weird size) and the power/communication line, I used 14/4 THHN cable. I also had to buy a little condensate pump since I went through the attic and didn't put the hole through brick facia.

Most mini splits have a single 5/16" port on the high side, so you don't need a manifold. A simple pressure gauge is OK just to monitor the nitrogen pressure.

Edit: forgot to mention that you need to be careful when re-installing the valve core. Maybe have an extra handy. Practice this with the nitrogen first so you don't accidentally release your gas. You have to screw it in under pressure and you have to do it all by feel.

Ohmthis · May 5, 2026

Advice on the flares.Always, Always , Always ream/deburr the line after you cut the copper. Do not use the factory flares on a line set. Make your own. I use a special flaring tool made by yellow jacket. If used right, you basically can’t screw up a flare. Check the flare for rough spots or cracks. It’s possible to smash a piece of swarf into the face causing a bad spot (that also means you didn’t deburr it!) or tighten the flare tool down too much (not with the yellow jacket. It has a clutch to prevent this) Also, use the flare nuts that are on the equipment. I like using nylog on the flares and threads to help seal any little issues.

jshillin · May 5, 2026

Ohmthis said:
Advice on the flares.Always, Always , Always ream/deburr the line after you cut the copper. Do not use the factory flares on a line set. Make your own. I use a special flaring tool made by yellow jacket. If used right, you basically can’t screw up a flare. Check the flare for rough spots or cracks. It’s possible to smash a piece of swarf into the face causing a bad spot (that also means you didn’t deburr it!) or tighten the flare tool down too much (not with the yellow jacket. It has a clutch to prevent this) Also, use the flare nuts that are on the equipment. I like using nylog on the flares and threads to help seal any little issues.

Thanks, I didn't even consider them coming with bad flares. I was ordering it with 13 foot lineset so I didn't have to cut/flare. I doubt I use the flaring tool often, do you have any decent recommendations? I added Nylog to my list.

todd_fuller said:
I recently did my mini split, a Daikin R32 Atmophera. I did a lot of reading before buying tools. I wasn't in a rush to get it commissioned so I allowed myself to maybe not have everything ahead of time. This is the list of tools I used:

- 5/16" core removal tool (mini split is different from normal AC units + the end fitting is 1/4 so you can use normal AC hoses with it)
- 1/4" AC hose for nitrogen purge/pressure test
- nitrogen regulator
- vacuum pump + new vacuum oil (new oil is real important to getting deep vacuum. I bought a used pump and with old oil it wasn't capable of pulling below 500microns, with new oil I got the system to 120 microns)
- vacuum gauge (I got an Elitech full-range version, ended up buying a BluVac micron gauge because it had a nice vacuum leak rate detector that worked over several hours. Elitech would have worked just fine, getting the vacuum right is really important and it isn't as simple as turn on vacuum until it's a small number, at that vacuum, even gas in the hose values makes a difference and it's meaningful to see the vacuum vs time curve)
- (vacuum hoses - optional, but makes vacuuming it out a lot faster. They are bigger)
- flaring tool (mine didn't have a lineset and I needed to cut to length, make sure it's an 'orbital' flaring tool. My factory flares weren't that pretty either)
- tubing bender (I got a cheap-o ratchet one and it was OK. I also got these internal Easybend benders which go inside the copper to prevent a kink when you hand bend)

A note about second-hand vacuum gauges. I read a lot about gauges and seems that most of them can get ruined by oil contaminants. Some have are more resistant or clean easily and some have replaceable parts, but buying used means it could give bad readings.

The supplies you may need extra are the condensate line (sometimes they are a weird size) and the power/communication line, I used 14/4 THHN cable. I also had to buy a little condensate pump since I went through the attic and didn't put the hole through brick facia.

Most mini splits have a single 5/16" port on the high side, so you don't need a manifold. A simple pressure gauge is OK just to monitor the nitrogen pressure.

Edit: forgot to mention that you need to be careful when re-installing the valve core. Maybe have an extra handy. Practice this with the nitrogen first so you don't accidentally release your gas. You have to screw it in under pressure and you have to do it all by feel.

Thanks, that's a lot of great info. What core removal tool did you end up using? I see a lot of recommendations out there, but also a lot of other people saying the recommendations I found were not good lie Appion, YellowJacket and Navac.

Ohmthis · May 5, 2026

jshillin said:
Thanks, I didn't even consider them coming with bad flares. I was ordering it with 13 foot lineset so I didn't have to cut/flare. I doubt I use the flaring tool often, do you have any decent recommendations? I added Nylog to my list.

Thanks, that's a lot of great info. What core removal tool did you end up using? I see a lot of recommendations out there, but also a lot of other people saying the recommendations I found were not good lie Appion, YellowJacket and Navac.

If you feel like you will do several more systems, then good tools will pay for themselves. I have a

Yellow Jacket 60278

For my flaring tool. It’s around $200, but it’s stupid simple to use. The cone self centers and spins as it flares. It essentially molds the copper as it spins instead of pushing it out. It locks at the bottom and you know to stop. The CPS Blackmax is nice as well. It has a built in clutch and is a bit cheaper at around $160 or so. I prefer the Yellow Jacket for comfort and leverage.

As far as vacuum parts are concerned, Appion all the way. I have a core removal tool that has had zero issues. I have yet to rebuild it (you can get rebuild parts) and it’s been in use for more than 10 years now. I also use an appion vacuum rated hose that has a 1/4” fitting on one side and 1/2” fitting on the other (1/2” hose). While that is not required for a mini split I believe, it does really help with pulling a deep vacuum quickly. I use a Bluvac micron gauge as well. Again, it’s been a brute and is in use for over 10 years. Research and ask here if a certain type, brand is suitable.

pembol · May 5, 2026

If you have time, you can probably skip the micron gauge and even the nitrogen test. You can spend some time vacuuming the lines to get them as evacuated and dry as possible, then leave them under vacuum for at least 24 hours (or preferably longer) to make sure you have no leaks. A micron gauge can detect a leak much faster as it has far better resolution than a normal gauge set, so it is a must have if you are an installer on a 2 hour job. But you will see the leaks eventually on a gauge set if you let it sit long enough.

As for the nitrogen pressure test, this is great for identifying and then locating leaks when the lineset is at positive pressure, but if you have been careful with your install and passed a longer vacuum test, it is pretty unlikely you will find a leak on a positive pressure test.

You don't want to end up spending $900 on tools to install a $700 minisplit!

jshillin · May 5, 2026

Ohmthis said:
If you feel like you will do several more systems, then good tools will pay for themselves. I have a

Yellow Jacket 60278
For my flaring tool. It’s around $200, but it’s stupid simple to use. The cone self centers and spins as it flares. It essentially molds the copper as it spins instead of pushing it out. It locks at the bottom and you know to stop. The CPS Blackmax is nice as well. It has a built in clutch and is a bit cheaper at around $160 or so. I prefer the Yellow Jacket for comfort and leverage.

As far as vacuum parts are concerned, Appion all the way. I have a core removal tool that has had zero issues. I have yet to rebuild it (you can get rebuild parts) and it’s been in use for more than 10 years now. I also use an appion vacuum rated hose that has a 1/4” fitting on one side and 1/2” fitting on the other (1/2” hose). While that is not required for a mini split I believe, it does really help with pulling a deep vacuum quickly. I use a Bluvac micron gauge as well. Again, it’s been a brute and is in use for over 10 years. Research and ask here if a certain type, brand is suitable.

Thanks, that Yellow Jacket looks great, but may be a bit overkill for the few that I plan to install. How about something like this? https://www.amazon.com/Super-Stars-Flaring-Tools-Refrigeration/dp/B0995GR79P/?tag=atomicindus08-20

Ohmthis · May 5, 2026

pembol said:
If you have time, you can probably skip the micron gauge and even the nitrogen test. You can spend some time vacuuming the lines to get them as evacuated and dry as possible, then leave them under vacuum for at least 24 hours (or preferably longer) to make sure you have no leaks. A micron gauge can detect a leak much faster as it has far better resolution than a normal gauge set, so it is a must have if you are an installer on a 2 hour job. But you will see the leaks eventually on a gauge set if you let it sit long enough.

As for the nitrogen pressure test, this is great for identifying and then locating leaks when the lineset is at positive pressure, but if you have been careful with your install and passed a longer vacuum test, it is pretty unlikely you will find a leak on a positive pressure test.

You don't want to end up spending $900 on tools to install a $700 minisplit!

I beg to differ on this. The manufacturer wouldn’t have this pressure test step in their installation process if it was important. The system doesn’t run with a vacuum on the lines, it runs with pressure. Pressure pushes the fittings apart (where you can see leaks with bubbles) while vacuum ***** them together and takes a much longer time to show the leak.

Even if he spends $900 on a $700 system, $1600 is drop compared to a professionally installed system.

Ohmthis · May 5, 2026

jshillin said:
Thanks, that Yellow Jacket looks great, but may be a bit overkill for the few that I plan to install. How about something like this? https://www.amazon.com/Super-Stars-Flaring-Tools-Refrigeration/dp/B0995GR79P/?tag=atomicindus08-20

I know nothing about it. From what I see from the pictures posted by customers. There are lines or tiny grooves around the flare face. It should be smooth. Those rings will create a tiny gap. It also could be that the person didn’t deburr the copper well before they flared it. If I think about it, I will do a quick step by step on a flare and post it later.

pembol · May 5, 2026

Ohmthis said:
I beg to differ on this. The manufacturer wouldn’t have this pressure test step in their installation process if it was important. The system doesn’t run with a vacuum on the lines, it runs with pressure. Pressure pushes the fittings apart (where you can see leaks with bubbles) while vacuum ***** them together and takes a much longer time to show the leak.

Even if he spends $900 on a $700 system, $1600 is drop compared to a professionally installed system.

I am not an HVAC tech, but I have installed or helped install a few minisplits. I have access to UHP nitrogen so I have done a positive pressure test, but I have also never found a leak this way that didn't also show up on the vacuum test. I think my sample size is about 4, so I am not saying you will never find a leak that appears at positive pressure over vacuum, and if you have nitrogen you may as well do it (and if you do this often, you should have nitrogen).

What I am suggesting is that if this is a one off install of a low cost system, it may be worth the risk of forgoing the nitrogen test. You should still do a bubble test on all your fittings as soon as you release the refrigerant.

It may not be the absolute best practice, but it is not required in the installation manual for many of the cheaper splits (including Costway) and many DIYers get away without doing it.

Ohmthis · May 5, 2026

This is a better view and a side by side comparison. Notice the grooves or rings in the face of the one on the right vs the smooth face on the left.

Ohmthis · May 5, 2026

pembol said:
I am not an HVAC tech, but I have installed or helped install a few minisplits. I have access to UHP nitrogen so I have done a positive pressure test, but I have also never found a leak this way that didn't also show up on the vacuum test. I think my sample size is about 4, so I am not saying you will never find a leak that appears at positive pressure over vacuum, and if you have nitrogen you may as well do it (and if you do this often, you should have nitrogen).

What I am suggesting is that if this is a one off install of a low cost system, it may be worth the risk of forgoing the nitrogen test. You should still do a bubble test on all your fittings as soon as you release the refrigerant.

It may not be the absolute best practice, but it is not required in the installation manual for many of the cheaper splits (including Costway) and many DIYers get away without doing it.

No judgement here. Where a low cost install turns into a headache later is the small things. Best operating procedure is to pressure test “Before” releasing the refrigerant. If you don’t have the tools/parts to pressure test, I’m willing to bet you don’t have the equipment to recover the refrigerant if a leak is found. Then there is the cost of more refrigerant if you dump it or loose it all. The OP came with questions and I’m doing what I believe is the best for them. I wouldn’t advise someone to build their first high performance race engine without a torque wrench either. I hope you understand I’m not trying to sh!t on you.

dcg9381 · May 5, 2026

I just stick with the pre-built lines myself. Do you guys use flare seals? I used these on the last job...

Kaizen · May 5, 2026

I was in the same boat 4 years ago. I ran a 3 zone LG system in my house. I made the mistake of taking the covers off of the linesets before final flare and connection and it was like that all summer so i had to get a tank of nitrogen to blow through the zones after connection then fill and vacuum. If i recall it moved any water vapor out better then just vacuum.
There was a guy that did a full install vid on youtube. I followed him exactly including all tools he used. Not high end but not budget either. I did need to get 2 stage 5 cfm big vacuum pump as my automobile one just could not pull it down enought. I did have 3 zones though.
Mine has been running problem free for 4 years. Use for heat in the crossover from winter to other seasons instead of running boiler. dont regret my decision for a minute.
Go slow and follow steps exactly. Once you release that refrigerant if it aint perfect you're spending money on pro's

Ohmthis · May 5, 2026

dcg9381 said:
I just stick with the pre-built lines myself. Do you guys use flare seals? I used these on the last job...

I have not used them, but have been curious. I may pick up some. I wonder about expansion and contraction of the copper. If there is a chance of the nut loosening up and then a leak is present.

todd_fuller · May 5, 2026

I got Appion for the core removal tool, Hilmor for the flaring, and Yellow Jacket for hoses. There's a few good brands out there. I just picked the cheapest of the quality ones. I looked at eBay a fair bit before purchasing and it's wild out there. Either stuff is totally worn out or it's near-new cost. I did find a good deal on a Navac pump w/ built-in gauge (although gauge wasn't good for anything but a rough guess).

There are also some new fittings out there from SmartLock which doesn't require any flaring, just screws together.

I'm with Kaizen w.r.t. doing the testing, etc. Even if the mini split isn't $$$, if the lose the refrigerant and burn out the compressor, you're in it for the tools cost to do it right the first time. Besides, this is GJ where anything worth doing is worth overdoing.

Edit: If we're talking about linesets, I bought a 1/4" x 5/8" x 1/2" x 50' Flare Lineset from surplus city for $150. Would recommend. I'd also recommend the heavy duty insulation wrap if you have to pull it around anything. I got the regular stuff and pulling it around a rafter down into the ceiling tore the insulation a bit which took some time to repair.

gagecalman · May 5, 2026

Do you have access to R32? If you have a leak you will need it once you fix it.
Mini splits are not charged with gauges. If you have a leak you have to remove all of the R32 and weigh in the new charge. That's why it's important to do a leak check and pull a good vacuum prior to releasing the refrigerant that's in the outdoor unit.

If you haven't already watch some of his videos on mini splits.

https://www.youtube.com/@acservicetechchannel/featured

sjvicker · May 6, 2026

For anyone recharging or adding due to a longer line length I found a good place to get R32 online was Royal Refrigerants. The scale and reverse thread fitting needed to connect to your gauges can be bought on Amazon.

pcmeiners · May 7, 2026

dcg9381 said:
I just stick with the pre-built lines myself. Do you guys use flare seals? I used these on the last job...

Use these on all my splits. These flare seal are great. Tested them on one of my first splits under pressure and under vacuum. They seal at 600psi or at the lowest micron level every time, they seal with only partial torque ( like using only 1/3 of the recommended torque in testing even at 600psi or 25 microns), or repeated loosing/tightening.

Ohmthis said:
I have not used them, but have been curious. I may pick up some. I wonder about expansion and contraction of the copper. If there is a chance of the nut loosening up and then a leak is present.

For the price of these flare seals they are cheap insurance, they cover many issue including poorly made flares. My flares are done correctly but vibration/contraction over years are not an issue with these installed.

Mind you I also use a tiny amount of Loctite blue behind the flare and on the king valve cap threads. The only negative of the seals is they need to be carefully placed on the sealing surface as they can come off or misalign if not placed correctly. Basically the seal surfaces are coated with a thick, dry coating of Loctite blue.

Question becomes do you spend a few dollars on the seals or do you want to deal with a leak, even if it 1 out of a hundred installed units 5 years down the road.

Raisedonadeere · May 7, 2026

sjvicker said:
For anyone recharging or adding due to a longer line length I found a good place to get R32 online was Royal Refrigerants. The scale and reverse thread fitting needed to connect to your gauges can be bought on Amazon.

Thanks for the reverse thread fitting heads up. I have done several Mini split installs and lived off a tank of 410a I bought when you could just order it without a certification. Don't ask me when that was. I just got on line one day and saw it on amazon and ordered it, and no questions asked. I don't know if that was a mistake on their part or just the way the regs were then, I am guessing 2015 or there abouts.

One of the frustrations of installs going from r22 to 410a then to Mini split 410a was getting the fitting sizes sorted out in my head, Between my vacuum pump, gauges, cutoff valves etc.,

Something always needed an adapter forcing a halt in the project while I sorted it out. I hate it when that happens and it always happens (tongue in cheek)

bluedog225 · May 7, 2026

@danski0224

Recommended True Tech Tools videos on HVAC installations. They were excellent. I’d do exactly what they do.

danski0224 · May 7, 2026

jshillin said:
Any help is greatly appreciated!

Honestly, all of the tools needed are listed in the installation manual for equipment like this.

jshillin · May 11, 2026

I've been gathering tools. I have most, but not all quite yet.

CPS VP6D 2 Stage 6CFM Vacuum Pump
CPS VG2000 Micron Vacuum Gauge
Appion Core Removal Tool 5/16"
1/2" Vac Hose
Elitech DMG-2SE Digital Gauges with Hoses & Adapters
Nitrogen Bottle with regulator and hose
Clutch Flaring tool kit with pipe cutter, deburring tool, metric and standard flares
Flareseal
Nylkog Blue
Big Blue Brush On Leak Detector
internal pipe bender protector

I have to sit down and go through it to see what else I'm missing before I place my order for the mini split.

gagecalman · May 11, 2026

Torque and crowfoot wrenches.
Do not put anything like Nylog on the back of the flare or the threads. It will affect the torque and you will over-torque.
Just a small amount on the face.

jshillin · May 11, 2026

gagecalman said:
Torque and crowfoot wrenches.
Do not put anything like Nylog on the back of the flare or the threads. It will affect the torque and you will over-torque.
Just a small amount on the face.

Thanks, I already have torque wrenches and crowfoot's in the garage. I know I have the right size for the 1/4" line, but I'm not sure what size wrench I'm going to need for the 1/2" line.

jshillin · May 15, 2026

gagecalman said:
Torque and crowfoot wrenches.
Do not put anything like Nylog on the back of the flare or the threads. It will affect the torque and you will over-torque.
Just a small amount on the face.

I saw that the large fitting was either going to be 27mm or 29mm, so I went ahead and picked up a JB Torque Wrench kit for HVAC so it has all of the correct sizes. I also had my Nitrogen tank filled. The only that that hasn't been delivered yet is my Micron Gauge, but it's supposed to be here Tuesday. I also ordered the mini split last night.

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