DIY Mini Split Install: 3 Regrets After 1 Year of Use

Now that it's been a year since I installed my mini split, here are my three biggest regrets regarding the DIY Mini Split install process as well as an update on how my mini split has performed through the harsh winter and the hot summer. #minisplit #tosot #heatingairconditioning

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[markpang]

This is how that DIY YouTube channels SHOULD do it. Update, be transparent about errors, possible improvements, afterthoughts, etc. Thank you for the integrity, time, effort, and information.

[garymendham]

I know you're planning to cover the refrigerant lines but, when you wrap them in the tape do it from the bottom towards the top. If you start at the top the overlap is the wrong way and feeds all of the rain etc inside the wrapping which is exactly what you're trying to avoid

[rockboy]

Little note for everyone, by NEC code your breaker will be sized by the Nameplate on the unit. Never size your breaker to your wire, yes 10 gauge is rated for 30 amps, but the unit was rated for 15. So, 15 Amp breaker then you size your wire accordingly. Oversizing your wire does not hurt but is typically reserved for lengths of 100ft+. This is to keep your voltage drop from being more than 3%. Never never never oversize your breaker unless you want to destroy equipment or burn down your house. Hope this helps!

[mikebaldwin]

I used your original video to do my first Mini Split and found it VERY useful. I was also happy to see these updates. I especially like DIYers who are willing to put out there what mistakes, or improvements they would make. For that, you got a new subscriber. Luckly, I have electrical experience and used both the correct wiring and the breaker. I also cut the pipe to the exact size and flared the ends. All in all - It has been keeping me cool during these weeks of 105 deg+ days here in Texas.

[alanmainwaring]

Great to see video's dedicated to DIY people. Here in Australia any authority, trades people completely discourage any DIY. You will not see any videos on DIY electrical installation for example done by Australian's. Every non-qualified person is treated like an idiot in this country. With the internet and videos like this any intelligent person can do a really great job on almost any technical install.
I recently installed an 8KW Fujitsu Mini Split I decided to buy the vacuum pump and gauges and Nitrogen, Flaring tools, trunking and so on. The unit has been running virtually 24hrs a day in heat mode and has saved me so much money in electricity costs. Soon be entering summer where temps are expected to get to over 40 degrees C. Thank you so much for the Americans that have a can do attitude with these videos.

[jamesrobinson]

THHN is for use in a dry environment. Outside conducts are considered to be a wet environment, not dry, so THWN is the correct conductor rating. Usually, conductors are dual rated THHN/THWN so you may be good to go.

[SageMaven]

I have had your 1st vid on repeat for a minute now planning my install, and am So grateful for this update. My husband passed unexpectedly and I'm thrown into in a whole new world of diy by myself, so I'm trying to sponge everything. And while a lot can't be trusted on YT, I have faith in the candor in which you present yourself and your information. Thank you!

[ehudgavron]

Thanks for the great tips, and also for explaining the WHY and the HOW and mistakes. We learn from others, and without knowing what others have tried incorrectly can't learn! Just "do what I do" is not enough. So, thank you again for that.

Some comments:
- A 14.4KBTU unit is $100 more than a 12KBTU unit and the process is the same. Suggest to your viewers to figure out their sqft and usage and go with the biggest unit.
- Voltage is not relevant wo wire gauge but amperage is. For up to 15AWG 12AWG is sufficient and 10AWG is fine too. You lose no money points for using 10 gauge wire
- You want to share the interior unit ground with the outside unit, OR bore a hole and put in a copper rod and use an external ground. Avoiding that last option means 10/4 not 10/3, with RED and BLACK being hots on two-legs ("split phase") and white for neutral/common and green for ground.
- If humidity is a common thing in your neck of the woods, DO NOT OVERSIZE THE UNIT. It will run less, and waste more time removing humidity before cooling, then sit dormant as the temperature climbs. In contrast a properly sized unit will remove humidity and run MORE of the time, contnuing to keep the temps cool and humidity low. The same WORK is accomplished and the same ENERGY is spent only over a cycle that has smaller "humps" and longer run times for the smaller unit. Don't undersize -- that will cause it not to be able to "keep up" which we call "unable to satisfy [requirements of cooling or thermostat]"
- You could still cut the excess cord. You just need a vacuum pump and a gauge set. These are $100 at Harbor Freight (yeah I know....) and you can return them after you use them if you like OR rent them out to your neighbors at $10/pop and have it pay for itself in under a year. Personally I'd just leave them up on a shelf for the next time an HVAC unit dies. (Which if you're going there, get a universal start capacitor and refrigerant bottle as well).
- You're spot on in changing the breaker down to 15A .. and maybe explaining why would help. SOMETHING needs to be the first thing to blow. We want that to be NOT the motor, NOT the wiring, but the breaker. Sized appropriately it will do exactly that. For a 12K BTU unit (up to my fave the 14.4KBTU unit) a 15A breaker is sufficient. That's also what sits behind most of our north-American receptacles (NEMA 5-15R).

[steveroberts]

When you change the breaker, if it really bothers you, put colored tape on the wire ends to make them ANY color you want. (The wires wont care) 😊

[crabwalk]

Nils, it takes quite a person to publically admit any shortcomings. Well done, you! I like knowing your opinion after time of use. Thank you for posting.

[davidhatesentropy]

I’m so glad you made this update. The original really bugged me for all these issues, but great that you took comments seriously and reconsidered.

[michaelziegler]

One install tip . I did not open both refrigerant valves during the installation. So I got an FO error message. That led to all sorts of checks, and when I finally opened the valve, the error message remained. I gave up and called the HVAC folks in. Everything tested perfectly....the only thing needed was a HARD RESET...cutting all power to the unit. Problem solved. I told TOSOT to add this to the suggested solutions for us very problem creative DIYs . Thanks for a great video. It actually made me believe I could do the installation. Saved thousands and the extra 200usd for the HVAC visit was more embarrassing than costly.

[adamdejesus]

Definitely the line covers. I didn't like the color of the plastic so I used 2 coats of spray primer and then painted with the same exterior paint I use on my siding. Looks sharp!

[scaryperson]

I wouldn't worry about that 10 gauge wiring. I think it's a non-issue. The idea is that you only want to use THHN with the concern being heat. However, with the 16 gauge being enough and you stepping up to 10 gauge, you'll never heat that wire up unless it's a dead short. At which point a 15 amp breaker will trip.

[GoodlyEarth]

I absolutely love follow-up videos like this. I always wonder how installs are doing after a few months and years. Nils, thank you for this informative video.

[robklaproth]

Very well done! I just finished my Mr. COOL ones. I went with Mr. Cool for the 7 year warranty as well as the fact that I didn’t want to mess with flaring. I got the line set covers and they are a ROYAL pain to install! You have to drill anchor holes in the side of your house and install anchors. All those holes make me worry about moisture intrusion but we live in so California so not as big of a deal. I plan on priming and painting to match the house when I repaint the house. I also really HATE the coil and will probably get a professional HVAC contractor to come and trim my lines for me. It voids the warranty on Mr. Cool so I may just have to live with it. It’s on the side of my house where no one can see it and I rarely go so, not a big deal. Ironically we have had a cooler summer in San Diego so I haven’t had to run the unit too much but when I do it freezes me out. My electrician ran THHN inside the conduit, 10 gauge. One thing he did to save me money is we got a 500 foot roll of wire and he just did 3 cuts, one for each color and then he color coded it at each end. You don’t need to go to Home Depot and Pay $2 a foot to custom cut 3 colors of wire for you when you can get a bulk roll of wire from an electrical supply place or the depot.

[slidewaze]

I had the same issue with sun rot on the line set insulation. So, ..I installed the cover kit a year after I installed our 18k Pioneer and it seemed to help the unit cool since the line set is on the SW side of the house. It's a good investment. Oh and it's been cooling really well even while it's been 117°F outside. Good video topic. 👍

[JCWren]

I put a 12K BTU Pioneer unit w/ the WiFi module in the basement in my last house. I cut the lines to length, pumped them down, etc. It worked really well, except for two things. One was that the drain line would occasionally get blocked by algae growth. It had the recommended slope and wasn't very long. As a result, several times I had water back up and run down the wall. I'm not sure if it was supposed to have a sensor for that or not, but if it did, it didn't work. The other problem with that model is overall temperature setting. It uses the handheld remote as a "thermostat", but it didn't do a very good job. I would much prefer to have a hardwired thermostat as an option. If the unit can't "see" the remote (which is an infrared based, not radio), it falls back to the internal sensor. Since mini-splits are usually mounted closer to the ceiling, it'll always thinks it's warmer than it actually is. But as far as cooling and heating the basement area, the overall reliability, and just how darn quiet they are, they're awesome.

[JohnDoe-huve]

I used your initial video to help me so thanks for that. I actually ended up installing three units in a large shop and one regret I have is that I installed them to the outside wall using L-Brackets very similar to yours. I find the units to be quite loud in terms of vibrating the walls and I regret not putting them on a pedestal or something that was isolated from the building exterior. Several companies make stands for these and I wish I had used one....

[raysoucie]

Months ago, I watched your Original Install video-- I opted for a(24, 000 BTU) Senville Unit... I called the Company directly and got a nice Discount plus Free freight -- I decided to make a set of videos(Senville Heat Pump Install Series Parts 1-7)-- Everything went smoothly, except with the Evaporator drainage hose-- On my 1st Night of operation I, LITERALLY, filled 2 five gallon buckets from running my Central Air Unit....Thanks for taking the time to explain and SHOW people on how to do the installs