DIY Mini Split Install - All the Things Nobody Shows You

i am a regular guy. 75 years old. installed ours in two leasure days. no problems. it has worked perfecty for 3 years now. we love it.

(Absolutely new to doing any HVAC DIY) After watching this video, and a few others, and reading a ton of comments, I installed two TOSOT 12K mini-splits, and I am extremely impressed with how quiet and effective they are. I intend to install two more to completely replace my A/C and baseboard heat. A few notes on my install. First, buy torque wrenches and be certain of your spec for the line size. Brass nuts are soft and this joint is critical. I almost certainly would have under torqued if I had gone by feel alone. If you have to cut and flare your lines, put money into a good flaring tool. I tried a low end tool ($33) that I bought from a local HVAC shop and I wouldn't consider the flare it made to be useable. I then purchased a BlackMax tool, and it worked extremely well. However, when I got to the 1/4 line, it wouldn't grip the copper. From another forum, I learned that 1/4" copper is probably not 1'4", and YellowJacket recommends wrapping some worn sandpaper around the pipe when flaring. This worked perfectly, and I was able to flare. Regarding vacuuming down the lines: The manual says to simply remove the manifold guage lines from the service port after testing a vacuum, that will draw ambient air in until the valve closes while you remove the gauge lines. I spoke with TOSOT, and they recommed the following: After testing for vacuum. Very carefully open the refrigerant release on the small line, just until the manifold guage reads a positive pressure and then close it. Then remove the manifold guage line from the service port as quickly as you can. You will feel a small amount of refrigerant release as the valve closes. Then release the refrigerant from both lines. Seriously appreciate all the comments from @rbfour5 and others, and well as this video. With the current rebates and tax credits, and installing myself, I'll probably have all four installed for under a grand. For all you "pros" out there who love to rip on those of us who DIY, this is why we do it. We don't have an extra $10K laying around to hire a local company that might not actually do a better job than we can. Sure, I would absolutely LOVE to hire someone else to do the endless projects around my house, but with even the local handymen in the area charging $75/hr, I sure can't afford it, so here I am building cabinets, roofing my garage, and installing split-units, just to name a few. Cheers to everyone else who learns and does.

As a DIYer I've installed 7 or 8 of these on my house, shop, etc because contractors want ridiculous prices for installation. I have to remind myself how to do it every time and this is by far, the best video on the subject, since, as he says, he covers every, single, step.

I went ahead and did a pad and mounted the outdoor unit on it. My thoughts were less noise from the outdoor unit would get transmitted through the wall, into the inside space. My neighbor mounted it to the wall and did say he could hear the compressor through the wall. We get a lot of water from the indoor unit, but it is humid here. I really wished i'd seen your video before putting in our units. Very well done!

As other have mentioned, you should use a 15 amp breaker set on this circuit. The wire gauge is irrelevant when sizing things. You size for the SMALLEST wire used. In addition, I would have use the red and black wires and capped off the white one. You have no neutral line going out, just two live wires. The white wire suggests it is a neutral wire which it is NOT! Yes, this works, but I wouldn't do it that way. If you do use 14-2 wire, I would wrap the white wire with red tape to indicate it is a live wire, not a neutral. Note that the wire to the AC condenser from the cutoff switch has red and black wires, and no white wire.

Areas to be aware of: 1.) You should never use the flare nuts that are included on the refrigerant lines. These should be removed by cutting the flare off the ends of the tubing, and use the flare nuts included with the mini split equipment, and make new flares on your tubing. This should be made with a flaring tool designed for mini splits. The angle of the flares on mini splits are different than the traditional refrigeration flares. 2.) All flares MUST be torqued to the manufacturers specifications. You cannot “feel” the correct torque, and “good and snug” is subjective. 3.) It is acceptable to coil excess refrigerant lines to stay within the minimum required lengths. However, any refrigerant system with coiled up lines must be in a horizontal plane. When you coil up lines in the vertical plane you create oil traps. The oil in the compressor circulates with the refrigerant in droplet form. The oil cannot return to the compressor if it collects in the bottom of the vertical trap of these refrigerant lines. I work for a mini split manufacturer, and the above installation problems are what we see in our Top 10 Installation Issues. Overall you did a commendable job with your installation. I would only caution anyone viewing this video to make the three changes I observed above to ensure trouble free operation and performance of a DIY mini split installation.

As others said, use the 15 amp breaker. Spare out the neutral since you have 2 leads otherwise it is good practice to color tape the neutral for anyone working on it in the future. Depending on your location I probably would avoid using EMT outside and use PVC or rigid. IMC would work, but I don't see it used very much. It is also a good idea to leave the wire a little long and pass the breaker then come back down so you have some service slack.

Thank you for this video. It made my mini split install go smoothly. The unit you installed is much like the one I purchased, so evertying was almost exact.

Once you have pulled a vacuum do not just disconnect the line, that will allow air in, release liquid line (small pipe service valve) with an Allen key up to 10psi or more then remove the line, this makes positive rpessure in the pipe preventing air getting in when you take off the blue hose

This is a pretty good introduction & better than most, but it would be outstanding if you edited it, leaving in the mistakes but showing corrections where possible (like red/white wire connections & breaker size) & providing all the correct information and tips from the comments made. It would provide the “why” and really help the DIYer to understand & prevent common mistakes.

Awesome job and it saved you thousands of dollars not having to hire an HVAC guy and an electrician! It works and all the little tweaks I can follow once I start mine. Seeing this video showed me how simple it is and how cheap the tools are to complete the job. No need to hire a contractor I will give myself a warranty!! 😎👍🏾 thanks again!!

I just finished installing my 2nd mini-split and it was from a vendor that was remarkably similar to the Tosot unit you installed, including the broken plastic cover that the delivery company broke when it was dropped on that end of the condenser. I had my fingers crossed that it would still work in spite of being dropped. It did, thank goodness. Some cautionary points for your audience. Consider using a Line Cover for the external lines to protect the lines from UV damage, wind vibration, or anyone playing around with the lines. I also recommend that you cut the lines to length and route them to the condenser so that the oil won't pool up in the excess line. It means a flare tool and more work but it could be necessary. The last suggestion is to resize the conduit to a larger size or remove the Romex jacket because if an inspector saw that they may fail you for exceeding the conduit fill ratio. The AHJ might also require a Fused Disconnect. Otherwise, it's a good illustration of the complexity of installing a mini-split.

If you're going to oversize the breaker (30A), then you MUST install a fusible disconnect with properly rated fuses (no more than 15A). By supplying that heavy gauge (#10, #8) wire to the unit from a 30A breaker, the small wiring inside the outdoor unit will be the weak link, and a failure in either the indoor or outdoor unit could easily start a fire because there is no way that breaker will trip before internal wiring melts. Just because you are using #10 wire doesn't mean you have to use a 30A breaker -- you could have just as easily used a 15A breaker. Also, the #8 wire of the whip was way too large for the terminal screws.

A little tip, use a long pilot bit the same size as the hole saw bit FIRST, so your holes perfectly align.

I really appreciate the time you took to put together this video. I used it as a guide to install my Senville mini split. Your step by step instructions were great as well as your parts list to buy stuff from Amazon. I would have never had known to get that adapter fitting to connect to the low pressure side while vacuuming the line. Thanks again and you really helped me and saved me a boat load of money!

Clear explanation. I'm not an electrician but I've heard you need to remove the sheathing on romex when running in conduit os it doesnt overheat (per code). Id also use the 15Amp breaker to protect the device - no law against oversized wire.

Watching the video and You are meant to leave the gauges on the service port until the valve on the suction line has been opened, when you open the suction line valve it closes off the vacuum port internally so it keeps the system under vacuum at all times, removing the gauges first will allow the lines to come back up to atmospheric pressure.

I just got to the end of the video. Very nice, btw. What I did was to cover what you have as the taped lines going from the outdoor to the indoor units with PVC drain spout. I cut out a big enough channel on the table saw and then fit it over those lines. It was a nice way to give it a trim look and add a bit of protection from the weather.

Just wanted to say thanks!! Installed my mini split today and this was my go to video when I had questions - Thanks again!

Thank you for this. I'm doing a room edition at my mother's where you can't tap into the existing ductwork (mobile home village) so I think a mini split is best option. Not sure if I'm going to tackle this by myself but it's nice to see how it's done.Again,thanks for taking the time to make this video.