Choosing the right brand for a mini-split

[Soundchasm]

Have you considered laying down some insulation under flooring in the cold room? It can make a huge difference. My small shop is on slab and I couldn't heat it very well with an electric heater. The heater would run continuously and it still always felt cold even after hours of running. I put down some foam interlocking flooring in there and the difference is amazing. Now I can easily warm up the place in an hour now. There are more elegant solutions for a nice finished room, but they make this stuff in colors instead of the industrial grey that I used in the shop if you want an inexpensive solution.

The wife would like to use the room more, and we're kicking around ideas. It's a tile floor. She mentioned a rug, but the room is the main traffic route for the dogs going in and out, and from time to time they're not in exactly pristine condition! ;-)

 

[peakbagger]

When I had my mini split charged by a tech I had run the copper lines but left them loose at each end. They were preflared but the tech cut off the flares and did a new set as he had had bad luck with factory preflares. The other thing he did was purged the lines with inert gas (I think it was an argon blend). He then pulled a vacuum and let the gauge set for about 15 minutes. He then charged the unit and pulled the required vacuum and let it set for about 15 minutes. I have read that its best to leave them overnight and see if there is any loss but expect few techs would.

I have regular AC only minisplit that I want to switch to a cold climate unit. The lines are foamed into my ceiling and would be bear to change. The tech I have talked to are very hesitant to reuse the existing lines even though its the same brand and gas type.

Manufacturers are starting to switch to CO2 reportedly they require even higher pressures

 

[sportbikerider78]

My 42kBTU unit is on its way. Shipped yesterday.

I will have 15k head, 15k head and a 12k head unit.

I have a friend that is an electrician and he will be coming to home depot with me to buy everything I need to install 2 20A fuses, run the cable inside, run outside to my disconnect, wire the disconnect and then to the unit.

Good times. 90F at my house yesterday but this next week or so is a nice temp to get things done.

 

[jeanw]

we happy with a bigger Samsung and a smaller Friedrich. course not used much since unfortunately not been here much cause of family problems. But its on now in LR. house is only under 1500 sq ft.
now if just could get a replacement remote for Samsung. No one will help. no eaters around. BIL and brother (in the trades) helped back in the the early years 2000's
just a saying

 

[sportbikerider78]

Interesting totally unexpected crossroads...
Boss called me last night and asked it I wanted to move back towards my hometown.

Now..do I install the mini split to increase home value or bring it with me to use on a new home that I will build?
I'm leaning toward install it for home value and ease of sale.

 

[begreen]

Congratulations. Hope the boss makes it worth your while. If so you will have to weigh the options like how soon you would move, hvac options in the new home, etc.

 

[peakbagger]

IMHO I would take it with you unless your local housing market is tight or the lack of AC is big impact to new buyers. I don't think you will get anywhere near what you spent to buy and install out of the house price. Folks rarely pay extra for mechanical systems, they will discount if stuff doesn't work to get deal but rarely will they pay for recent upgrades.

 

[sportbikerider78]

Thanks for the feedback. What I was thinking is that it would make me more competitive with nicer homes in the area. I have one of the cheapest homes on the block ($260-300k vs $500k+) and i would.like to get as much as possible.
AC isn't an absolute must in this area, but it certainly is a nice to have. Last summer had many many wks in the 90's.
I'm thinking that your average person that drops $300k on a home is going to want it.

 

[sportbikerider78]

Picked up the units today. Doing the wiring with a friend in the next week.
Exciting this project is finally kicking off.

 

[sportbikerider78]

Doing some parts shopping tonight.

Amazon has by FAR the cheapest pricing on line sets.
1/4" x 3/8" x 50' insulated $99 shipped.

Unfortunately, I can't order a continuous 100'-120' set and cut my own. Oh well. This is still the way to go.

 

[sportbikerider78]

Pics or it didn't happen, right?

 

[sportbikerider78]

All the wall units hung on Saturday.

Instead of buying a kit (for $15 each) to go between inside wall and outside wall. I bought a section of 3" pvc pipe and used a 3.5" hole saw. Fit was perfect. Because I was using a bigger than recommned hole, I needed to move the hole center up a big more then the template showed.

The template Mits. provides on the back of the bracket is downright awesome. Tons of holes. Perfect place to lock your tape measure into and measure the exact spot to 5 1/8" hole center. I could not have been happier with it.

 

[sportbikerider78]

Outside view

 

[sportbikerider78]

Complete

 

[sportbikerider78]

Some progress this weekend. Pad is poured about 4-6". Graded to drain, since we do have a lot of rain in our area. Main thing for me was to allow it to drain and float. Of course, just as I was finishing the pour it rained (t-storm) and I forgot to cover it, since it was a mad dash to get my tools out of the rain. The top is a touch sandy and flaky, which is characteristic of too much water. Whatever. Not a big deal. Most guys use patio blocks and this is exponentially better.

The condenser footprint is 40x15 and I poured a 48x22.5.

The picture makes it look out of square on the left side, but it isn't. The wavyness towards the foundation is kids hand prints.




My electrician friend went to HD with me to get supplies. Wow. 8/3 wire is pricey. $187 for 50'. Got a disconnect for $15. 40A breaker for $10-20 and some misc other supplies.
Remaining lineset and channels to conceal the linesets against the siding coming in today.

Have a heating and cooling professional over in a few days to quote connecting linesets, pulling a vac, charging the system. If he will install the linesets for a little more money, I'll have him do that too.

 

[peakbagger]

Are you putting the outdoor unit at ground level?. Generally they get put up elevated off the ground in snow zones well above the typical snow pack height to keep the unit from getting filled up with snow.

 

[sportbikerider78]

Are you putting the outdoor unit at ground level?. Generally they get put up elevated off the ground in snow zones well above the typical snow pack height to keep the unit from getting filled up with snow.

That is true. This will not be a source of heat in the winter and (you can't see it in the pic) but it is under my deck by about 4-5'. That is why I placed it under there...to keep it free of snowfall. Getting it packed with snow is a valid concern when it is being used for heat.
After the install is complete, I'll also create a small roof for it under my deck to keep rain from dripping between boards onto it.

 

[Soundchasm]

If you can't have a little fun with concrete, what's the point?? ;-)

You've probably already thought of it, but do you have access to hose off the radiator, or fins, or whatever you call it? Here, deep in cottonwood territory, I have to do mine at least twice a year.

 

[sportbikerider78]

If you can't have a little fun with concrete, what's the point?? ;-)

You've probably already thought of it, but do you have access to hose off the radiator, or fins, or whatever you call it? Here, deep in cottonwood territory, I have to do mine at least twice a year.

Yep...about 10 feet away.
Good call.

 

[fbelec]

how many tons is your unit?

 

[sportbikerider78]

how many tons is your unit?

3.5

 

[fbelec]

i ask because there is a minimum amp circuit and a maximum amp circuit rating on the units. if it goes bad and burns up the company can refuse the warranty if to big a breaker is on it. i think it may be 30 for that. with those inverter compressors there is no surge current like a regular compressor so there is no need to worry about the circuit start up current

 

[sportbikerider78]

i ask because there is a minimum amp circuit and a maximum amp circuit rating on the units. if it goes bad and burns up the company can refuse the warranty if to big a breaker is on it. i think it may be 30 for that. with those inverter compressors there is no surge current like a regular compressor so there is no need to worry about the circuit start up current

The min rating is 31.9A max is 40A. There is no 31.9A breaker that I know of.

Our plan is to run 8/3wire on a 40A breaker.

 

[Ashful]

The min rating is 31.9A max is 40A. There is no 31.9A breaker that I know of.

Our plan is to run 8/3wire on a 40A breaker.

Check with a real electrician on this, but I believe there’s a requirement that all dedicated breakers must be sized at rated load divided by 0.8, such that rated load is never more than 80% of breaker capacity on a dedicated line. This would dictate a 50A breaker, if we used the max load number, but I’m wondering if they’ve already done that math for you here. In other words, rated load = 32A/0.8 => 40A breaker.

 

[sportbikerider78]

Check with a real electrician on this, but I believe there’s a requirement that all dedicated breakers must be sized at rated load divided by 0.8, such that rated load is never more than 80% of breaker capacity on a dedicated line. This would dictate a 50A breaker, if we used the max load number, but I’m wondering if they’ve already done that math for you here. In other words, rated load = 32A/0.8 => 40A breaker.

My friend is an electrician that is helping with the wiring.

Here is all the info the installation manual provides. You can see it says "Max Fuse Size 40A".



Everything I have read and seen on line about this unit is that it doesn't even pull the minimum 31A at start up. These do not have a motor start massive amperage draw because they don't have a 'stupid' AC motor...they have an inverter driven AC motor which is being driving by a programmed startup profile.
The unit will be running around 15-20A most of the time. Again,,from what I have see from videos online.
BTW,,,Mitsubishi makes some of the best inverters/Variable Frequency Drives (VFD's) on the market. As a sales engineer, they are a great product to represent. The only bad part (for the salesman) is that once you sell them, you never sell the same one again!