Mini Split install

[340RedCoupe]

Is it really possible to DIY a Mini Split?
The facts:
New construction
750 sq ft 12' ceilings
Radiant in the floor, no hot water source yet
Mini split will be used for bump up heat and A/C
Me:
retired
done many construction projects for myself
complete rewire and replumb of house, no fire or flood
complete remodel of house, added complete second floor, 2 baths, kitchen, built garage from scratch, building shop currently subbed the framing and concrete
built structures
restored cars
never been afraid to try a new project

are some brands of M/S easier to install? I got a quote for this job from a HVAC company and he was at $6000.00. I can buy the unit he quoted for about half of that and I cannot imagine this would more than a full day job. I have already roughed in the power. So, what do you guys think? Should I try this? Do these units come with any type of directions? Do I need a HVAC guy to charge the unit? I do not have any way to vacuum a line set. Do these units contain on freon? Are the lines precharged?
Thanks

 

[Hubmonkey]

Is it really possible to DIY a Mini Split?

Yes Mr Cool units are DIY.

are some brands of M/S easier to install?

Mr Cool are DIY

I got a quote for this job from a HVAC company and he was at $6000.00. I can buy the unit he quoted for about half of that and I cannot imagine this would more than a full day job. I have already roughed in the power. So, what do you guys think?

I had my mini Split installed by a HVAC guy. I did the electrical roughed in and had the placement ready and easy to get to. he was in and out in a few hours.

Should I try this?

If you have the proper tools to pull a vacuum and have some experience in HVAC, go for it.

Do these units come with any type of directions?

There are lots of videos around to help.

Do I need a HVAC guy to charge the unit?

Most units that are not DIY (Mr Cool) require a licensed HVAC person to install and charge these for the warranty to be valid.

I do not have any way to vacuum a line set.

You will need a vacuum pump and other tools to do one that in not a DIY setup like the Mr Cool.

Do these units contain on freon?

Yes the condensers are charged with Refrigerant

Are the lines precharged?

I think the mr Cool has precharged line sets. My Unit the guy made his own line sets.

I found that some HVAC companies throw out a ridiculous number because they don't really want to do them or are always trying to hit a home run. Not trying to start the argument of how much trucks and tools and parts on trucks and insurance cost , I get it.

I was lucky in the fact the guy who did mine had installed a MS in my moms house at the lake and was cool about coming to my place and doing an install, even though I was almost 2 hours away from his usual area.

 

[rixtrix1]

Your description fits me to a T, less the radiant heat in the floor( I live in Phoenix ). I did everything to build my shop except the slab and shingles,so a minisplit should be a snap for me, or you. Search YT for minisplit installs. The ones I watched make it super easy, just the time to set the unit, hang the airhandler, run the tubing, connect the wires and open the valves on the lines!

 

[mepstein]

Go on YouTube, watch some videos. Decide if it’s something you can do. Bottom line, many people do it themselves.

 

[chinboys]

Try to visit an HVAC-R vocation school and speak to the instructor to see if any of his students want a weekend project.
The student(s) reinforce their learning by doing and are under the instructor's oversight.

BTW, other than Mr. Cool products, many of the other brands will void their warranties if their systems aren't installed by "certified and licensed" installers.

 

[WildBill]

I did a 24k DIY Mr.Cool install in my shop about two years ago, was pretty straightforward and has worked great since. Just was running fine at -15F. Probably pretty inefficient at that temp, but was putting out warm air still. My skillset is about the same as yours. Main issues I see for mini-splits on various forums are leaking connections and damaged electronics from voltage spikes. This is across all brands. Most are made by 2-3 main companies, I think the majority are made by Gree.

If you want a warranty you will have to get a Mr.Cool DIY set, vendor is very important for support, a lot of people recommend Ingrams Heating and Air for good support.

If your OK with a 18 seer setup this is a good deal - https://iwae.com/shop/24k-btu-18-se...t-pump-split-system-wall-mounted-ha21762.html

I probably spent $350ish on breaker, disconnect, surge suppressor (very highly recommended to protect control board, install it at outside disconnect) wire, outside mount, etc. Was wiring shop anyways so didn't need a separate permit.

Only tool like items I had to buy, no vacuum needed on DIY Mr.Cool.

Nylog for connectors - https://www.amazon.com/gp/product/B008HOSQQQ?tag=atomicindus08-20

Crows foot flare wrenches for properly torqueing connections, something like this, check your fitting sizes on whatever you buy - https://www.amazon.com/dp/B01LWUIZWM?tag=atomicindus08-20

Happy to answer any questions you have about my setup.

 

[theoldwizard1]

Is it really possible to DIY a Mini Split?

Yes !

The big difference between DIY systems and professionally installed is DIY systems come with a specific length of pre-charged tubing. You need to order surplus and store the extra somewhere. Professionally installed systems cut the tubing to length and typically braze it on. Then pressure and vacuum test it and charge the system.

Mr. Cool is the king of DIY systems. Mitsubishi and Fujitsu are tops in professionally installed.

The cost of the tools kills the savings on non-pre-charged systems for DIY.

Radiant in the floor, no hot water source yet

Several mini-splits companies are starting to offer heat exchangers as an option. This would create hot water for your floor and domestic hot water. (This type of system has been available outside the US for many years.)

 

[theoldwizard1]

Yes the condensers are charged with Freon

Picking a nit ...

Freon was banned years ago. Most mini-split systems use R410. There are other alternatives.

 

[danski0224]

Is it really possible to DIY a Mini Split?

Pick whatever you think you need, download the installation manual, read it at least once, then decide.

 

[Hubmonkey]

Picking a nit ...

Freon was banned years ago. Most mini-split systems use R410. There are other alternatives.

there I fixed it

 

[rockcrawler]

You might look at Pioneer. Their mini splits are DIY w/warranty. They are reasonably priced and have a pretty good reputation for quality and customer service. Their units are pre-charged and you can purchase them with whichever line length works best for you. I’ve never done AC work, but I’m in the process of installing 2 - 24K Pioneer mini splits now. These are the units I bought from them.

Pioneer® 24,000 BTU 21 SEER Ductless Mini-Split AC Heat Pump

Pioneer Inverter++. Our most powerful and efficient system. Ultra-quiet, easy to install, and highly capable with 24,000 BTU capacity and 21 SEER efficiency.

www.pioneerminisplit.com

 

[brewchief]

Picking a nit ...

Freon was banned years ago. Most mini-split systems use R410. There are other alternatives.

Freon was simply a dupont trade name, ir reality it's simply R-22 or R-12, IIRC duponts trade name for R410a was Suva, some manufacturers called it puron or environ in the beginning before simply calling it R-410a.

R-22 is no longer manufactured new but refrigerant that is recovered is sent back and remanufactured and is currently readily available.

 

[bluedog225]

Subscribed

 

[RPhil]

Mr. Cool and Pioneer both offer DIY systems. Mr. Cool has pre-charged linesets and Pioneer has a pre-charged outdoor unit. With Mr. Cool, you will need to coil up the additional lineset length if you have more than you need based on the indoor and outdoor unit locations. With Pioneer, you could cut the lineset to length, but would then need to vacuum down.

There are a variety of videos on YouTube showing the installation of either option.

Pioneer seems to be a cheaper option, but with slightly more work for installation due to the vacuum pump requirement. They have a "Hyper Heat" version now, which they market as "Hyperformance." I am likely going this route for my garage and basement. Here is the 24k version of that unit: https://www.highseer.com/products/p...air-conditioner-hyper-heat-pump-full-set-230v.

You may want to get a load calc to understand your capacity requirements. I have a ~600 sq ft garage that is insulated well, with 13' ceilings. I got a free, old 12k mini split unit that was able to hold temp (71-73) during the summer when I was out there, but ran constantly and did not ramp down. It is being replaced and I am likely to go with a 18k unit, if not a 24k. Mini splits can turn down quite a bit (the specs are available online for the models you are considering), but you still don't want to drastically oversize. It also depends on your use case- how often will you be out there? Will it be running 24/7 so it is always the temperature that you require? If so, don't oversize too much as it is unnecessary. If you plan to bump it up and down regularly, you may want a little bit more of capacity to reduce the amount of time to reach your desired temperature.

Based on your skillset, I don't think you will have a problem installing yourself.

Good luck!

 

[carmaniak]

Absolutely, you can DIY a mini-split installation given your experience. Choose a brand with clear instructions. Pre-charged units exist. Rent a vacuum pump, and ensure no refrigerant leaks. Follow local codes, get necessary permits. Save money, but prioritize safety and precision. Good luck!

 

[340RedCoupe]

Thanks for all the reply’s. You guys have convinced me to try this. I’m sure I will have more questions along the way with the install.

 

[jjrbus]

I had a wee bit of experience with AC from doing my vehicles plus a few tools. Installing a MS is not rocket science but does require the right tools and just a smidge of common sense. The videos available are much better now than they were a few years ago. One tool far too many skip is a flair gauge. You don't know how to do this you have no experience so buy a flair gauge if doing non DIY units. Flairs are the fail point for most DIY installs, I also have AC specific torque wrenches.

https://www.supplyhouse.com/Navac-N...t8wiaeWZeuj4E_bW99rZDZDg75QFWrDRoCjFUQAvD_BwE

 

[340RedCoupe]

I’m currently considering a Mr Cool with a pre-fabbed up line set so no needed vacuum or charging required. I like a nice clean install but some extra length to deal with on the line set is not the end of the world.

 

[pcmeiners]

"One tool far too many skip is a flair gauge. You don't know how to do this you have no experience so buy a flair gauge if doing non DIY units."

I bought one. From experience you do not need one. On your flare tool base have the copper tube slightly above the base die, start with a 1/32th make a test flare, see if it fits in the flare nut. If loose try 1/16th. Most it will take is 2-3 tries to find out your perfect flare. One you have visibly seen the perfect height above the die, you can do it without measuring every time.

 

[Crowbarman55]

I’m currently considering a Mr Cool with a pre-fabbed up line set so no needed vacuum or charging required. I like a nice clean install but some extra length to deal with on the line set is not the end of the world.

I installed a Mrcool in my garage a year and a half ago.. I had never done one before but am not afraid to try. Added the 220 to the sub panel myself ran all the wires, its was not that hard to do. I am very patient and like things to be done right so I took my time and went over everything a couple times.
Except for not pushing the breaker all the way back in tight before flipping the power back on and causing a slight spark and breaker falling out it all worked fine and still does.
Todd

 

[JunkBonds]

My son and I installed a Daikin between and new years a month ago.

Easy peezy if you have a flaring tool, gauges and a vacuum system. Otherwise, not so much.

 

[pcmeiners]

As to difficulty, as stated if you have the tools it is easy. Installed 5 minisplit in my house/garage. I installed the linesets within the walls/floor joists which is much more work and tedious (after the first couple) but worth the effort. It would be wise to get your EPA 608, requires some study but not difficult. As mention do not cut corners, leaks and damaged equipment are expensive, if you must cut corners due to your nature Stop Now.

 

[pcmeiners]

"I can buy the unit he quoted for about half of that and I cannot imagine this would more than a full day job."

You can get a very high efficiency low temp unit for 1/3. For a little over half you can just about get all the tools you would need and the unit. FYI, I easily heat a 1080 garage with a 12k unit, a 9k would do it. Go for it, take your time, your retired

 

[JunkBonds]

"I can buy the unit he quoted for about half of that and I cannot imagine this would more than a full day job."

You can get a very high efficiency low temp unit for 1/3. For a little over half you can just about get all the tools you would need and the unit. FYI, I easily heat a 1080 garage with a 12k unit, a 9k would do it. Go for it, take your time, your retired

I agree. Wholesale cost on a 1 1/2 ton Daikin plus the lines, disconnect, wire, etc cost us about $1,500US. It took 2 of us all day to install it. It is tedious work that you cannot rush.

I also forgot to mention the tank of nitrogen you need to pressurize the system first before you evacuate the system.

 

[sjvicker]

Definitely DIY it. I was on the fence about it but Will Prowse has a good video that I'll end up following when I do mine:

The tools dont seem that expensive and there's the potential to save a bunch of money. Yeah, you might give up your warranty or have to pay an expert if you screw up but you'll likely still come out ahead and learn a new skill.

 

[JunkBonds]

I also forgot to mention the torque wrench with a claw foot for ensuring all connections are to spec. My son made the claw at his work and everyone here already has a torque wrench, right.

 

[rockcrawler]

Just finished mine. I used these line set benders to assist in making bends without worrying about kinks. They work pretty good, but can be difficult getting back out if a tight bend is made.

 

[brianh]

I have installed 4 pioneer units on our house, two in 2021 and two more this last summer after being impressed at how well the first two worked.

Follow the installation instructions they are simple and clear.

A word of caution on youtube installs I watched two and in both each guy did something wrong.

One video the guy vacuumed down the line set, the next step he was supposed to do was crack the refrigerant line and re close to have pressure before removing the vacuum line he just removed the line letting air back in.

The second video the guy just put the refrigerant valve on full blast and proceeded to spray it all over while removing the vacuum line.

I recommend mounting them on their own stands the first one I did I mounted to the side of the house and I can hear it at times through the wall. The others are on stands above the snow line and it is silent in the house.

 

[340RedCoupe]

Thanks again for all the replies and suggestions. Sorry for the delay in posting, retired life is very busy, I can't imagine I used to also have time for a full-time job. (But I don't miss it)
So here we go with questions and observations.
I have done SOME research and educating myself on these units so I'm becoming more confident that I will be able to do this. The only tools I think I'm missing are a vacuum pump, flare gauge and a set of line benders. It appears to me that these line sets are copper tubing with standard single flares, not doubles as in automotive brake lines, correct? If so, cutting to exact length and re-flaring should be very doable. Flare tool, torque wrench and crow foot line wrenches I have. I have made, formed and replaced many brake lines on cars, so I assume this is similar. I am fairly **** about things being neat looking and organized so a rat's nest of spaghetti looking wires or hydraulic lines isn't going to fly with me. This leads me to a question: Have any of you run line sets in PVC pipe in wall cavities? My shop is framed with 2 X 6's so I have a 5-1/2" deep stud cavity, this is new construction so no drywall or insulation yet. The inside unit will be above a man-door and about 9' -10' from the floor and the outside unit will be directly outside. I'm thinking of a 2" or 3" white PVC DVW pipe chase in the stud cavity with sweep 90's on both ends will work. With this no ugly line sets running down the exterior of the inside or outside of the wall. I want to get some opinions on this before I drill any holes through the siding. I really like the idea of only needing to vacuum the lines and the condenser comes pre-charged, so no measuring or sourcing of the gas to charge the unit. If the charge is in the condenser, varying the length of the line set will affect the amount of charge, won't it?
I look forward to any and all comments and I'm sure I'll have more questions.
Thanks

 

[Innovate1]

I was just viewing some videos on installing minisplits in RVs. Apparently its a big boost in efficiency and also gives heating. Downside is it doesn't just drop in where the AC was. Somewhere along the line I learned Oreilly loans vacuum pumps and gauge sets. Think it has to be returned in 48 hours - not nearly as lenient as Autozone on time but I suppose you could just borrow it again if needed for longer. I just saw that Home Depot sells minisplits - no idea if the brand is any good.

 

[Innovate1]

As to making the line runs look neat they do make covers to run down the wall. That's going to be much easier to do that fishing the lines through conduit with bends. When I had an AC installed in my shop the inside unit was on a high platform so the line set came out about 8' up. I asked them about covering the lines and they threw that in for no extra cost so they can't be too expensive. It also keeps the sun from deteriorating the line insulation if the location gets any sun. The house lines only get very early sun but after 20 years it's in bad shape.

 

[racecougar]

As far as flaring the lines goes, I would recommend picking up an eccentric flaring tool rather than trying to use a flaring tool for brake lines. They can be had cheap, and produce a very fine finish. https://www.amazon.com/gp/product/B01CR4VC4E/?tag=atomicindus08-20

I'll also recommend using Nylog Blue at your connections.

Regarding the charge and line length, you'll find most mini splits will have a published line length range for the included charge. Stay within that, and you'll be fine.

 

[DB2]

I have "DIY-installed" about a dozen mini-splits and agree with all the advice above, especially using Nylog on the connections. Make sure you are using a 45-degree flare tool, and not a 30 or 37.5. I've discovered most "pros" are idiots when it comes to mini-split installs.

I bought all the right equipment (micron gauge, vacuum pump, Yellowjacket flaring tool, nitrogen tank, etc) and it was about $600 to start with, but it has more than paid for itself. I also bought a fancy tubing bender but have only used it once (with mini-splits).

In Asia there are literally millions and millions and millions of mini-splits. I've watched guys install them there, and I've never seen them use a vacuum pump or micron gauge or pressure test with nitrogen. To purge the line set they just loosen one of the flare nuts and then crack the valve to flash out a bit of refrigerant, then quickly tighten the flare nut and job done. I've seen guys do this hanging by 1 hand 20 stories in the air. And guess what, nearly all of mini splits "just work"!

 

[pcmeiners]

No one is stopping you from skipping any steps in the recommended procedures, if you like gambling.... it is a free country.

 

[Ilikeike]

I've installed two.
Did everything BUT the final connection and refrigerant release.

I wanted the lines cut to length exactly how I wanted so it looked good.

It just wasn't worth it to me to buy the tools. think I paid $200-300 to have a tech do it. He checked for leaks and made sure it cooled and heated.

 

[Notgrownup]

I did my own install except for cutting & flairing the lines and pulling vacuum. I paid a local guy $200 to do it. Bought everything from Alpine Home air. Blueridge brand.

 

[dscheidt]

I was just viewing some videos on installing minisplits in RVs. Apparently its a big boost in efficiency and also gives heating. Downside is it doesn't just drop in where the AC was. Somewhere along the line I learned Oreilly loans vacuum pumps and gauge sets. Think it has to be returned in 48 hours - not nearly as lenient as Autozone on time but I suppose you could just borrow it again if needed for longer. I just saw that Home Depot sells minisplits - no idea if the brand is any good.

home depot sell a bunch of brands, and in most, lists the full line up, so I expect they're listing what their suppliers list. They have them as the special buy of the day fairly regularly; sometimes they're a deal, sometimes not. I bought a Hessaire branded 18K btu/hr 23-ish seer unit from them last summer, it was drop shipped to the store. it's a midea made unit, just like most of these are. Works fine, the controls ****, just like all the midea units. It's cooling my basement, where I have my ofice. i used the heat a little bit in the fall when it was cool enough in the basement, but not cold enough to heat the hole house. Made heat a couple weeks ago at -10 (claim is -4), but I was just testing, and didn't run it for long as the boiler was running.