Mini Split a second question

[Ron Citerone]

So I take it the line set on mrcool is fairly easy to shape. Sounds pretty direct compared to a flare and evacuation for a first timer. I saw their video but wouldn’t mind hearing from a creeker who did it.😉

[Jim Becker]

The last one I got from Lowes came with 16 ft line sets, the last from Amazon was 12 ft. But neither were pre-charged line sets.

I was referring specifically to the MrCool DIY systems which the OP asked about.

[Jim Becker]

So I take it the line set on mrcool is fairly easy to shape. Sounds pretty direct compared to a flare and evacuation for a first timer. I saw their video but wouldn’t mind hearing from a creeker who did it.

Yes, it is, but you must take great care regardless, especially since it's pre-charged and expensive to replace. (DAKHIKT!) You do this slowly and carefully at the tails from the indoor unit and the last couple of feet at the outdoor unit. The larger coils of "extra" that would remain near the outdoor unit are less sensitive.

[Ron Citerone]

Yes, it is, but you must take great care regardless, especially since it's pre-charged and expensive to replace. (DAKHIKT!) You do this slowly and carefully at the tails from the indoor unit and the last couple of feet at the outdoor unit. The larger coils of "extra" that would remain near the outdoor unit are less sensitive.

Thanks Jim and others. DAMHIKT is how I learned a lot of what I know! I don’t mind learning from others who learn that way too! 😀

[Ronald Blue]

I'm not to concerned if I have issues down the road. I'm confident my HVAC guy will assist in repairing mine. He recommended I get Mr Cool. However mine weren't the DIY version. He came and shortened the lines and leak tested before charging the system. So no coils of excess line on mine. They worked great until it was cool enough that no AC was needed. I don't heat with them so I don't know how well that side of them work.

[Michael Schuch]

I have installed a Fujitsu single head mini split and a Mitsubishi 3 head mini split in my home. When I installed my Fujitsu many years ago I paid an AC tech to come out and do the final evacuation. He did NOT follow the Fujitsu directions (He also stunk of pot). They clearly stated to charge with Nitrogen, look for a pressure drop, evacuate then look for a pressure rise. He also charged me $350 for an hours work (several years ago). The 3 head Mitsubishi mini split I installed myself.

Tools:
vacuum pump - extra vacuum pump oil
YellowJacket eccentric flaring tool made for R410 flares.
Gauge / line set.
Nitrogen tank - gauge and fitting adapter for gauge set.
Nylog flare sealant (AC guy had never heard of it).

I skipped the recommended expensive micron vacuum gauge (so did the AC guy).

I will never use an overpriced under trained AC company guy again. I also walked my boss through installing his Mitsubishi mini split. It took him 2 tries to get a good seal on one of the flare connections but it has been working fine for a year now. My boss is smart but doesn't have a lot of home improvement experience.

When I do a pressure test then vacuum leak test I let both sit over night... which gives me much more confidence than the 45 minutes the AC tech waited!

[Tom M King]

I also pressure test with Nitrogen overnight and note the temperature of the lines both days to allow for any difference in pressure. I don't skip, or skimp on any tools. I replaced one lineset in a rental house that leaked down as you watched the gauge on the nitrogen regulator. It was leaking inside a wall that I didn't want to tear into.

I left the vacuum pump on my truck AC system too long one time, and compromised an O-ring, so I want to know how much of a vacuum I have on something.

[Bill George]

Tom you are doing things the right way!

I installed my Mitsubishi mini split on recommendation of my son who is service manager for a large Union commercial HVAC/R company. They just do not have issues and that's what he wants. I worked in the exact same business for many years and we were taught the correct way to do the work.

I have had limited experience with China made refrigeration systems and it does not hold up to the Japan based, designed units. The stuff I did run into suggests they are not that great at brazing and final leak detection.

[Thomas Pender]

Missed this earlier. I have significant HVAC experience from years gone by and with friendships, etc. One of the rules of thumb is that while the manufacturer is important for quality, the experience and skill of the installer is more important - as important as 75%. So, when I wanted a mini-split for my shop, which is in my basement, but on grade with my backyard and has two large garage doors, I hired the most reputable pro in our area to install the highest rated Toshiba unit. It has been a joy. Keeps stuff warm in the winter and not much of an issue in the summer since I have some walls that stay a fairly constant 55 degrees. What I am saying is I would never and I mean never, install my own Heat Pump HVAC system (including mini-split) unless I did it for a living. I am sure many will disagree with me and that is fine, but the warranties and quality you get bring peace of mind and longevity in my experience.

[Jim Becker]

I agree with you in many principles, Thomas, but relative to warranties, my "designed as a DIY system" for the shop has one of the best and longest warranties in the business. That part really comes down to what's in the fine print. Many systems that folks DIY actually do not have a warranty if a DIY install is done...it's a "gotcha" that gets missed during the buying process. That might be worth the risk for a detached workshop or garage system, but probably isn't the best idea for one's home.

[Tom M King]

Here is the quality we get from Pros around here. I ended up replacing this old line set. The house is old enough that I'm sure it was an R22 system to start with. We own it as a rental house now. What odds do you give that they flushed out the old lines. The old lines were in the wall behind brick. The vapor line was leaking.

Notice the crimp from hand bending the line, and the brazed joint that it looks like the one piece was "swaged" up with the little end of a ball peen hammer.

My other experience with a pro install was for a mini-split that we had to get in on very short notice for my 104 (then) year old Mother to move in with us. The system leaked, and when he came back to put in the half pound of 410a that had leaked out from his install, he charged me $400.

I do it myself for piece of mind and longevity. You don't know what you'll get when you call a "pro" around here. I have known some good ones, but they're all retired or dead now. I do it myself also out of desperation to get something done right, and for the quality of good work.

That 3/4" line was crimped enough to almost completely close off any flow of even vapor. A couple of other examples of pro work thrown in. One duct was heating and cooling the attic. The electrical line was soldered onto a connector that was really too small for the wire size-solder melted, circuit failed.

[Bill George]

My students in our HVAC/R program used to laugh at the pictures of stuff that was done in some of those areas. I had one take a spring break in Georgia and we all got a kick out of what passed for skilled labor down there. Most of the shops up here are either union or NATE certified trained in non-union shops. Need to be trained in the mini's and other complex systems. We also taught computer and CAD skills as part of the Program.

The cr@p posted above would get you fired!!