Mini split installation for a house

[Michael Schuch]

I'm learning a lot from all of your input, and I really appreciate it. I've ordered a 12k DIY Mr Cool from Zoro because they sent me a 20% coupon in the mail. Even though their starting price was higher the 20% made it cheaper than the other options. I'm wondering about a couple of other questions about the installation. I have some angle iron and a welder, so I am thinking of making my own wall bracket. I don't know how robust the bracket steel needs to be, or if what I have will be strong enough. I can also order one, but they look a bit under-engineered for what they cost.

Another question in my mind has to do with placement of the outdoor unit. The room to be cooled is abut twice as long as it is wide, with the short walls on the north and south. I had been thinking of having the inside unit about 2/3 of the way north on the west wall, with the outside unit on the north side. I could also put the inside unit on the north wall, but with 25' of line I should have enough to go around the corner, and it seems like not having it all the way at one end would help with distribution. It seems from the manual that the north wall is best for the outside part, to keep direct sunlight off it. I will be building a porch on the north side of the house next year, basically a deck with a roof over it and maybe a railing. I have not been able to find anything that says it is or isn't okay to have the compressor on a porch like this. In the meantime I'd just have to put a temporary roof/cover over the outside part to keep the worst of the rain and snow off it, if I understand correctly.

I went with the cheapest "known" online vendor I could find when ordering. I think the online mini-split dealers pretty near give the AC units away at very little profit and then stick it to you for all the installation supplies. The place I ordered my "non-MrCool" Mitsubishi unit from were charging double what supply houses were for the line sets, wire, mounts, etc. I have always had great luck with ordering stuff through Zoro. It usually arrives quicker than they promise. I think I ordered my last line set from Zoro because it was much cheaper than the other online AC vendors.

I made my own ground mount base for my last install out of 2" x 2" x 1/8" angle iron. It was WAY over built and 4 or 5 times the weight of a store bought base. If you look at how flimsy the store bought wall mount brackets are I think you would be VERY hard pressed to make one equally flimsy.

I chose ground mount because I have a concrete slab under our second story back deck. So the deck keeps the sun and snow off of the compressor. I also went ground mount because it is next to my daughters bedroom and I didn't want to wall mount it to where she could hear it. The outdoor compressor is so quiet that I doubt she would ever hear it if it were wall mounted. Most of the noise of a whole house AC comes from the unit starting up and coming up to speed. A mini-split does not have the initial spin up because it turns on slowly and only goes fast enough for the load where a central AC compressor usually has 2 speeds, full speed and off. The central AC compressor is about 15' away also under the same deck. I think (not being an HVAC person) that under a 2nd story deck is a perfect location as long as it is open with the ability of plenty of air flow. My ground mount compressor is about 6' in from the side of the deck so the hot air pretty much gets pushed out from under the deck instead of building up hot air under there. My compressor is held about 20" off the ground by my base to keep it above the dirt and debris.

North makes sense to minimize sun exposure heating the compressor while trying trying to cool. The top of my indoor head unit is t about 8' on a 9' internal wall and it is working very well.

My longest line run, to my 3rd bedroom, from the compressor that serves 3 bedrooms is about 35', around a corner and it has caused no issues. The only advice I would give for going around a corner is to use 4" line set covers instead of 3" so you can have a more gradual bend around the corner. I could find no line covers with an exterior corner piece available so I had to make my own out of a straight run piece by cutting it at 45 degree angles.

[Bryan Lee]

Me and a buddy installed my mini split, which came pre charged. We still needed a pump and a cylinder of nitrogen for pressure testing. Easy to get the nitro at a welding supply store for very minimal money.

[Bill George]

The test mode always runs runs the unit in AC mode.

Not all units are the same, mine had test modes in both heat and cool. Plus it has both the liquid line and gas line service ports outside the unit.

Having serviced heat pumps back in the early years (late 1970's) I watched for some of the stupid mistakes untrained installers did like not keeping it off the ground resulting in huge Ice dams around the unit, or installing under a deck. Since I worked commercial, nothing is more fun than working on a Carrier rooftop heat pump when its -5 F outside. As you might recall we were running out of natural gas and every manufacturer was building a heat pump and a lot were cr@p.

[Jim Becker]

Another question in my mind has to do with placement of the outdoor unit. The room to be cooled is abut twice as long as it is wide, with the short walls on the north and south. I had been thinking of having the inside unit about 2/3 of the way north on the west wall, with the outside unit on the north side. I could also put the inside unit on the north wall, but with 25' of line I should have enough to go around the corner, and it seems like not having it all the way at one end would help with distribution. It seems from the manual that the north wall is best for the outside part, to keep direct sunlight off it. I will be building a porch on the north side of the house next year, basically a deck with a roof over it and maybe a railing. I have not been able to find anything that says it is or isn't okay to have the compressor on a porch like this. In the meantime I'd just have to put a temporary roof/cover over the outside part to keep the worst of the rain and snow off it, if I understand correctly.

I suggest you wait for your final decision until you have your unit so you can visually judge the best position for the inside unit and lineset length/outside position with that additional input. There is not likely an overall ideal for both in many cases, so "eyes" on will help you zero in the best possible positioning for both. Your room usage matters in that because you may not want the indoor unit blowing directly on a "high use" place. It's not unlike a similar situation with a traditional duct...some positions are not comfortable for the humans for hot/cold direct air flow.

[Bill Dufour]

My first install of a outdoor unit has a minor issue. There is a simple slide off cover on one end where the lines and power connect. I should have prebent the lines into a sharper bend before final install. The cover jumps loose in a day or too. It hangs loose until I bother to clip it back. There is not enough slack to rebend the tubes. I should have tested the cover fit before charging the system. I made sure to bend and check several times on the next one I installed. I think it also has a screw to keep it in place as well as the clips.
Bill D

[Tom M King]

Tight bends are easy with a proper tubing bender, but really shouldn't be attempted without. This crimped line (sorry couldn't find the picture of the crimp) was installed by a "pro", and the reason I had to replace this line set. You can see the crimp in the short piece of old 3/4" line in the back of my truck behind the bender box if you blow the picture up. I cut that piece out to keep it as a souvenir.

The brazed joint was leaking. It wasn't done anything like properly. There was another leak behind the brick in the wall, so no choice but to redo the whole line set. This in a lake rental house. This is why I do everything myself.

These tubing benders do a pretty, tight bend, and I couldn't have done without them on this one job.

Line cover and line set from Supplyhouse.

[Bill George]

We used Imperial brand lever benders, they did a beautiful job. The guys that installed a lot of commercial jobs would anneal the hard refrigeration grade copper and bend, the soft ACR copper of course did not need too. https://www.amazon.com/Imperial-Tool...468520025&th=1

[Tom M King]

Those look good, but you need a separate one for each different size. The kit I bought works with all common sizes, and comes with the adapters to do "reverse" bends. It works plenty good enough. Like everything else, it's gone up significantly in price since I bought mine a couple of years ago, but the whole kit is still less than a 3/4" Imperial bender.

3/4 is the largest I've bent with it, but it did that with very little effort, and made pretty bends.

https://www.trutechtools.com/BlackMa...8-in-OD-Tubing

If I did it all the time, I'm sure the Imperials would come in good, especially when you need more than a 90 degree bend, and would be worth the extra cost.

edited to add: I needed the reverse setup mode to bend the old vapor line stub near the house in a fairly tight spot on that job. It worked fine. I'm not sure the Imperial handle could have been swung in that spot, but it could have been bent up to go another way.

[Michael Schuch]

In a previous post I believe I said that I order my supplies from Zoro at a great savings. I was wrong. I order my supplies / material through www.supplyhouse.com and have had excellent dealings with them. Their prices are a lot lower on things like line sets, fittings, plumbing parts, etc. And their shipping has always been VERY fast! (Faster than Amazon)

[Jim Becker]

Michael, I ordered the pad for my condenser from Supply House today...price was the same as Amazon and they could have it here Thursday instead of next week for under five bucks. I'd use them again for sure.

This puppy also arrived from Costco today...

IMG_2962.jpg

[Bill Dufour]

Costco ells mini splits? I knew they sold coffins and urns, special order only, not off the shelf.
Bill D

[Jim Becker]

Costco ells mini splits? I knew they sold coffins and urns, special order only, not off the shelf.
Bill D

They partnered with Mr Cool and sell systems at costco.com. These are not "in store" items. A "yuge" amount of products that Costco sells are not physically in the stores because of their nature.

[Brian Elfert]

They partnered with Mr Cool and sell systems at costco.com. These are not "in store" items. A "yuge" amount of products that Costco sells are not physically in the stores because of their nature.

I just wish Costco.com would show what is in the store and the current price like most big retailers these days. They do it a little bit now for some stuff, but they show the delivered price, not the in store price which is usually less.

[George Yetka]

You dont need to do it all. Just do the following.

-Run lineset. If its an easy path
-Flare connect the 2 ends of the lineset to the 2 pieces of equipment. Should only need a flaring tool for this but I recommend a flare sealant called Nylog it will make a better seal
-Condensate is easy
-Electric is easy.
-low voltage to stat or a wireless remote is easy

Hire someone to evacuate and charge This will cost a lot less than buying the tools.(DONT LET THEM SELL YOU REFRIGERANT) it is in the condenser already in 99% of residential single zone units.

[George Yetka]

Commercially I have installed 40 splits/ vrfs and on each of them we have a service guy follow behind for evac and charge. That is the most complicated part and requires the most amount of specialty tools.