How tough to install a 'non DIY' minisplit?

[HaiKarate]

How tough it is for someone with average mechanical ability to install a 'non-DIY' mini-split? I was going to go with a MrCool DIY 12K but apparently they don't like to sell those anymore (tried to order one lately? Last I heard was 'early June' last month and that has come and gone). I'm willing to buy some tools and go the more difficult route.

I'm thinking I can probably get away with a 9k(?) unit for my well sealed 14x24 room with R19 walls and R38 ceiling in this climate - what are the best brands in this BTU range for a 9k?

 

[shade]

Not hard. A non DIY will just require tools like the gauges and a vacuum.
Wasnt too hard to install my MR Cool 24k non DIY. I had a friend with the tools already and startup was the easiest part.

 

[thammel]

I did everything but the final evacuate and leak test on my 2 Mitsubishi mini splits. Not hard at all. I paid an hvac guy to do the final connections of the lines.

 

[Krfjkm]

I have 2 of them- paid a guy $400 to install them both. Turnkey deal— he does about 8-10 per day.

 

[glennm]

I did mine myself and paid $150 to a guy for the vac procedure. Hardest part of the job was finding someone that would do the final pump down for a reasonable price

 

[Syberia]

I'll know soon. From the videos I've watched, since I already have the equipment, it seems easier than an automotive A/C system, since no charging is required. Just make sure your flares don't leak!

 

[Terry D]

Installing the equipment is pretty straight forward. Doing the electric, as long as you are comfortable with doing it, can be simple also. Main thing like you said is all about those flares. Make sure they are done right and properly torqued. Leak test with nitrogen at 300 psi and check them with leak detector, evacuate down to 200 microns and let it sit for 30 minutes, make sure that it doesn't raise above 500 microns and release the charge.

Here is a good video on it

 

[Syberia]

Electric will be no problem, I just finished re-wiring (and insulating) the entire garage for two EVs.

 

[Yankeefarmer]

When I did mine, I bought a vacuum pump and manifold set, and a nitrogen regulator. Pressurized it using C25 shielding gas to 250 psi, and left it overnight. Next day, vented the C25 and evacuated. Did not have a micron gauge, and the manufacturer’s installation instructions did not mention one-they simply said achieve vacuum. I left the vacuum pump running for an hour for a 15 foot line set before sealing and then releasing the refrigerant. That was three years ago. System is now out of warranty that I would have had if installed by licensed guy and still performing great.

Others on here have said never to use CO2 for pressure testing. Allowable moisture content in C25 and nitrogen gas is the same, so not sure what the difference would be. YMMV and all that.

 

[HaiKarate]

Thanks for the replies and info. I will be watching the video(s) and reading up on this a bit today. My project has been on hold for a while as I've waited for this thing to get back in stock and I can't keep waiting indefinitely. Not too intimidated - just need to make sure I get the procedure down and collect the necessary equipment. Electric no problem and already roughed in.

 

[GRivera]

I have 2 of them- paid a guy $400 to install them both. Turnkey deal— he does about 8-10 per day.

He installs 8-10 units per day?

 

[malibu101]

When I did mine, I bought a vacuum pump and manifold set, and a nitrogen regulator. Pressurized it using C25 shielding gas to 250 psi, and left it overnight. Next day, vented the C25 and evacuated. Did not have a micron gauge, and the manufacturer’s installation instructions did not mention one-they simply said achieve vacuum. I left the vacuum pump running for an hour for a 15 foot line set before sealing and then releasing the refrigerant. That was three years ago. System is now out of warranty that I would have had if installed by licensed guy and still performing great.

Others on here have said never to use CO2 for pressure testing. Allowable moisture content in C25 and nitrogen gas is the same, so not sure what the difference would be. YMMV and all that.

Just wanted to add that I have C25 and 100% Argon on hand at all times but have no need for nitrogen.
In my personal repairing auto A/C systems I used Argon with no bad results. Surely more expensive than nitrogen but for my very seldom need it's what I have used.

 

[Krfjkm]

He installs 8-10 units per day?

Yep— mini splits are BIG in Texas!

 

[HaiKarate]

No worries about flares (although I'm well equipped to do so and have decent experience), as I plan to bury the excess line in a cavity inside the wall.

I am now shopping for a '1/3' HP/~4cfm chinese vaccum pump set on amazon and am leaning toward using 75/25 for pressure testing since I have it on site with my MIG welder.

 

[vavet]

No worries about flares (although I'm well equipped to do so and have decent experience), as I plan to bury the excess line in a cavity inside the wall.

I am now shopping for a '1/3' HP/~4cfm chinese vaccum pump set on amazon and am leaning toward using 75/25 for pressure testing since I have it on site with my MIG welder.

Why not shorten the lineset if you have the ability? To me, that was one of the biggest perks of the non DIY set. A friend with a hvac hobby helped me install it a couple years ago. it was pretty straightforward,

 

[Syberia]

I wouldn't coil up any lineset inside the wall. You'll get condensation and water damage/mold.

 

[HaiKarate]

Why not shorten the lineset if you have the ability? To me, that was one of the biggest perks of the non DIY set. A friend with a hvac hobby helped me install it a couple years ago. it was pretty straightforward,

I'd read of people doing this and it seemed to be the easier/foolproof route if I insulate the hell out of the lineset (I have some extra insulation laying around.

I may just shorten depending on how everything lands - I have a lot of leeway on placing the outside unit and virtually none inside.

Waiting to hear back from MrCool today - if no news then I have a pioneer unit sitting in my amazon cart I may pull the trigger on and see if I can get done this weekend.

 

[Terry D]

Just my own opinion, I don't use the factory flares than come on the line sets. I cut them off and make my own. If you do shorten your line set, don't go shorter than 10 ft. I know that's what Mr Cool recommends. I believe most of the other brands are the same also

 

[metlmunchr]

Just my own opinion, I don't use the factory flares than come on the line sets. I cut them off and make my own.

Same here. I've installed a couple and the supplied tubing package flares are too damn big. They look as if they're flared to the largest diameter that will still allow the nut to slip over the flare. No idea where anyone came up with the idea that's the way to size a flare.

Both units I installed were Pioneer, and their own instructions show the correct length of tubing sitting above the face of the flaring block to produce a proper flare, and it corresponds with the dimensions I've used in the past for replacing flared oil pressure lines and pressure operated unloader lines on larger equipment.

I shortened the line set by about 3 ft on the first unit I installed. Out of curiosity, I took the 3/8 od piece with the original flare and put a proper flare on the opposite end and attached 3/8 X 1/4 flare unions to both ends and torqued to spec. Capped one end and pressurized the other. The end with the original flare showed some small bubbles beginning around 550 psi. The other end with a correct size flare held leak free to 800 psi where I stopped. Nothing more than proof to myself that correct size flares do make a difference.

Bottom line, if you're installing a mini with flare connections and the flares on the line set are oversize, cut 'em off and re-flare. If you don't know from experience what "correct" or "too big" looks like, just grab a piece of scrap soft copper, deburr the end, set the end about one tubing thickness above the face of the flare block, and flare it. The result will be what a correct flare looks like.

 

[Sumboodie]

I have 2 of them- paid a guy $400 to install them both. Turnkey deal— he does about 8-10 per day.

It's certainly more than a ~45 min job.

 

[Sumboodie]

Are they economical to run with 0.20 kw/hr electricity? From what I understand it's like 200% efficient?

I'd like a quick way to heat the house. Have a wood stove and slab heat. Neither are quick. The stove isn't practical when I just need a bit of heat to get the spring or fall chill out.

Not overly in need of A/C, if it's hot in the house I just open some windows. Dehumidifing without heating up the house would be nice though.

 

[Yankeefarmer]

Are they economical to run with 0.20 kw/hr electricity? From what I understand it's like 200% efficient?

I'd like a quick way to heat the house. Have a wood stove and slab heat. Neither are quick. The stove isn't practical when I just need a bit of heat to get the spring or fall chill out

It will depend on outside temps and what unit you buy. My regular mini split in my old shop isn’t worth a darn for heat below about 32 degrees, but above that works well, especially when the air outside is dryer, so it spends less time in defrost mode. Our Fujitsu Halcyon works well down to low temps. We will use it in spring/fall before we can maintain a wood fire all day/night.

When I did the analysis for my new shop, I found that the heat pump efficiency at our $0.22 /kw-hr was favorable to an 80% efficient propane furnace because I pay about $3/ gallon propane because I just don’t use enough to buy large quantities.

 

[Git]

How tough it is for someone with average mechanical ability to install a 'non-DIY' mini-split? I was going to go with a MrCool DIY 12K but apparently they don't like to sell those anymore (tried to order one lately? Last I heard was 'early June' last month and that has come and gone). I'm willing to buy some tools and go the more difficult route.

I'm thinking I can probably get away with a 9k(?) unit for my well sealed 14x24 room with R19 walls and R38 ceiling in this climate - what are the best brands in this BTU range for a 9k?

oops, never mind. I saw Costco has one but it is 24k DIY

 

[NewShockerGuy]

So our AC/Furnaces are going to be replaced and while they were here I asked what a mini split would cost to put in the garage...

I was floored when he quoted me a Mitsubishi unit and total cost/install was $8k. Seems a bit excessively high to me. After all the videos watching online it does not seem like a hard process. I would need an electrician to run the power outside and have someone pull a vacuum (even though I have a pump and guages from car work).

I'm not hell bent on doing this myself. I'm all for people making money and earning a living but when we are already spending close to $25k for two furnaces/ACs, I thought for sure the mini split would be in the 3-4k range... Just seems crazy it would be that expensive to heat up a 21x21 two car garage with 11' ceilings.

-Nigel

 

[HaiKarate]

Thanks for the bump - I see I never followed up on this. I ended up going with the Pioneer minisplit and DIY install using a cheap chinese vacuum pump. Has been working great for about 2 years now!

DIY install took more time than it probably should have and was a bit nerve-wracking as I'd never messed with any of this stuff before, but like most things, it's not 'rocket science' if you can follow instructions.

 

[jjrbus]

Coiling lineset vertically has a technical name, it is called an oil trap! If you must coil, coil horizontally but a better solution is to run the lineset in a serpentine manner. Installing a mini is not rocket science but it must be done correctly. Being as I cannot see thousandth's of an inch I use a flair gauge, go no go. Hard to screw up with one.

https://www.amazon.com/dp/B076CMZBC8/?tag=atomicindus08-20

 

[pcmeiners]

"I was floored when he quoted me a Mitsubishi unit and total cost/install was $8k. Seems a "bit excessively high to me."

A bit excessive?......
The unit likely costs <2300, So they want close to $6000 in labor. Buy the needed equipment and DIY. The most difficult part is buying everything you need without making mistakes. Installed 2 units a couple months back, installing 4 more units within a couple months. I went as far as passing the EPA 608 universal and 609 tests so nothing stands in my way.

What will happen is the trade is so lucrative the market will flood so the present crew better make the money now, as the competition is growing, as are people willing to do their own installs.

"Are they economical to run with 0.20 kw/hr electricity? From what I understand it's like 200% efficient?"

An average minisplit is roughly 300% efficient .The very high efficiency units average approximately 400% efficiency. So for every 20 cent you spend on electric, at 300% you get the equivalent of 60 cents of heating or cooling. Obviously it cost more for very efficient minisplits.

Best advice... if you enjoy cutting corners, do not like self education or are just f**ing lazy, installing a minisplit is not for you. If you suffer from the mentioned it will cost you big time; we have a few on the forum who have paid the price.

 

[shade]

You can hire a decent handyman to do the install if you can't yourself.

 

[shade]

Dupe

 

[pcmeiners]

"When I did the analysis for my new shop, I found that the heat pump efficiency at our $0.22 /kw-hr was favorable to an 80% efficient propane furnace because I pay about $3/ gallon propane because I just don’t use enough to buy large quantities."

Unless you have a really ancient/inefficient heat pump, propane is always a lot more expensive.

My Fujitsu Hyperheats have an average 400% efficiency, that makes it a hair under 3 time more efficient than propane at $3 when the KW cost is $.20. When electric is $.20./kw the minisplit would run $14.65 per million Btu , propane $41.06 /million Btu @$3/gl . I run at $.17/kw so I pay 12.46 per million Btu

Plug in the parameters.....

https://www.maine.gov/energy/sites/maine.gov.energy/files/inline-files/Home-Heating-Calculator.xls

As to CO2, in the liquefaction process, the temperature could be above freezing, so moisture could remain, but there are drying methods used so technically CO2 should be OK from the tank. The only issue I see is if you have moisture in the lines, the CO2 mixes with it and forms carbonic acid. Copper and carbonic acid forms copper carbonate. Copper carbonate would form on the copper tubing and any electrical component within the closed system. How much would form during testing and purging with a lineset containing moisture, likely a minuscule amount. On the other hand nitrogen, argon krypton, neon, and helium are dry and totally inert, totally safe in a close refrigerant system for purging and testing. as long as they are vacuumed from the system before refrigerant is released/added.

 

[Hellpig]

Did a Pioneer 12k myself in December, no hvac experience. Bought a cheap vacuum pump and gauges off Amazon. No leak test, no vacuum tester. Just pulled vac for an hour and let her go!

Very happy with it, ordering a 18k Pioneer next week.

One of brothers has been doing commercial HVAC work for 40 years, so figured he'd bail me out if I screwed it up, lol.

He DID advise to leak test connections prior yo charge. But I ignored him


Worked out.

This time at least..

 

[Framton Nuttel]

I just installed a Mitsubishi 12k unit for our shed, which my wife uses as a home office.

It was a used unit that we got for next to nothing, with assurances that the refrigerant charge had been properly recovered into the outdoor unit and that the system was working well when it was last shut down.

There were enough quirks in the installation of this "recycled" unit that I might post a dedicated thread.

Overall, the process was easier than I expected given all the things that could go wrong - especially with a used (essentially discarded) unit.

I did a pressure test with some MIG welder gas (25%CO2, balance Argon), as others here have described, but to be honest I think it would have been enough to see if it held vacuum for a few hours. I was able to find someone local who "rents" the vacuum pump and gauges for $20/day, so the only tool I really had to buy was an eccentric flaring tool.

It's been cooling the shed without issues for about a week.

 

[Highbeam]

My Fujitsu Hyperheats have an average 400% efficiency, t

The good news is that to get an energy star rating the companies now have to produce actual data sheets so you can figure out efficiency at different outdoor temperatures. My Mr. cool goes from 300% at 57F to 214% at 5F. It drops pretty fast after that to 118% at -22F but I am not concerned with outdoor temperatures below 5F at my location. Hyperheat type "cold weather" minisplits often are more efficient at lower temperatures.

Bottom line, get the chart from the manufacturer. Easy to find at their website. You can see a wide range of efficiency depending on ambient temperature.

20 cents per KWH is actually pretty cheap. Even here in the PNW we are at 13 cents per KWH.

 

[pcmeiners]

"The good news is that to get an energy star rating the companies now have to produce actual data sheets so you can figure out efficiency at different outdoor temperatures."

It is not good news....
.
The minisplit manufacturers produce data but no one checks or challenges it, including the Federal, state private agencies; it an honor system amongst the hen guarding foxes, it a brotherhood. There are plenty of AHRI certificates, and minisplit manufacturer data releases which are falsified or the testing is manipulated. Do you know how many AHRI certificates are created with unverified manufacturers supplied data ?, out of multi thousands, a total of one has been challenged by AHRI, that is pathetic. Can you trust an AHRI certificate ?, absolutely not. JD Power and associates and AHRI can be equally trusted.

"20 cents per KWH is actually pretty cheap."

Imagine living in NYC or SanFrancisco

 

[purplezr2]

When I did mine, I bought a vacuum pump and manifold set, and a nitrogen regulator. Pressurized it using C25 shielding gas to 250 psi, and left it overnight. Next day, vented the C25 and evacuated. Did not have a micron gauge, and the manufacturer’s installation instructions did not mention one-they simply said achieve vacuum. I left the vacuum pump running for an hour for a 15 foot line set before sealing and then releasing the refrigerant. That was three years ago. System is now out of warranty that I would have had if installed by licensed guy and still performing great.

Others on here have said never to use CO2 for pressure testing. Allowable moisture content in C25 and nitrogen gas is the same, so not sure what the difference would be. YMMV and all that.

Basically did the same, except I used a micron gauge.

I'm only at the two year mark. I have had no issues other then the hinge door on my Pioneer head unit broke. Only effects cleaning the filters

 

[tunerwithkids]

Heres a full detailed video on Pioneer 12,000Btu in garage.

 

[My Old Tools]

When I did mine, I bought a vacuum pump and manifold set, and a nitrogen regulator. Pressurized it using C25 shielding gas to 250 psi, and left it overnight. Next day, vented the C25 and evacuated. Did not have a micron gauge, and the manufacturer’s installation instructions did not mention one-they simply said achieve vacuum. I left the vacuum pump running for an hour for a 15 foot line set before sealing and then releasing the refrigerant. That was three years ago. System is now out of warranty that I would have had if installed by licensed guy and still performing great.

Others on here have said never to use CO2 for pressure testing. Allowable moisture content in C25 and nitrogen gas is the same, so not sure what the difference would be. YMMV and all that.

I wondered about using my MIG gas. Glad it worked.

 

[Jim greengo]

I have 2 of them- paid a guy $400 to install them both. Turnkey deal— he does about 8-10 per day.

I'd like to see some pictures of his work ,cranking out that many in a day.

 

[pcmeiners]

"he does 8-10 a day".......Flares take too long .

 

[nsula_country]

He installs 8-10 units per day?

My thoughts also!

CT