Anyone running a mini split in their shop?
- Thread starter HITCH-
- Start date
Yes that is incorrect. The oil that lubes the compressor circulates with the refrigerant. The oil can pool in the loops and starve the compressor of lube. they should lie flat or horizontally coiled if that makes sense. At least that is the standard recommendation.
The nitrogen pressure test better for two main reasons. For one it is done at 300 to 500 psi and more likely to show a small leak. Use a special non-corrosive soap spray at the joints. The vacuum test will only get 14.7 psi pressure to try to get in. Since it doesn't come out you can't see bubbles with the soap so you wouldn't know where the leak was. The other reason is that if it does leak and under vacuum it will suck air and moisture into the system which is what you are trying to get rid of.
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Yes, that is what is generally recommended
I’m not an expert, so I’m just trying to understand if this is a real concern worth paying for, or if it’s another way to take advantage of customers. How much does it cost? Will pressurizing the system to 500 psi stress the solder joints?
I can see doing that test for an older system when trying to determine if there is a leak. It Seems like overkill in the case of a new mini split installation. The entire system would have been factory tested. (You would not want to pressure test the main unit where the freon is already sealed and under pressure). If there was a leak after it left the factory, it would show up when doing the final pressure checks. So at that point, the only concern would be the flare connection at the outside unit, (or perhaps a kinked line if care was not taken).
The hvac expert that did my final hook up and testing did not do the nitrogen pressure test and my system has been working fine. So did I just get lucky, or is it really necessary?
I think you are for the most part testing the connections. You do all of that before releasing the refrigerant so no, you are not testing the compressor. If you go with the fully DIY system with pre-charging even in the line set then I would just hook it up and go with it. But I start with the empty line set and make the flare connections at just the right length. I assume the pro just trusted all his flares and skipped the pressure test but to me that is an unacceptable short cut. I don't think there is any doubt that if a system has a leak it will be mostly likely be at a flare connection. I also use a torque wrench when tightening them. The only one that I had a leak with was one I actually over torqued and had to redo.
Mini splits usually use R410A which is a high pressure system, much higher than the old R22. So that makes the flare connections that much more risky.
Mini splits usually use R410A which is a high pressure system, much higher than the old R22. So that makes the flare connections that much more risky.
So I started getting bids for a tech to connect the lines and perform the vacuum and nitrogen tests.
I would be doing all of the rest of the installation myself.
The first bid came in at $450-500 and the second was for $800.
I would borrow or rent the tools and do that part of the installation myself but it would void the warranty.
The Mr Cool units that don't require these tests are looking better and better.
I would be doing all of the rest of the installation myself.
The first bid came in at $450-500 and the second was for $800.
I would borrow or rent the tools and do that part of the installation myself but it would void the warranty.
The Mr Cool units that don't require these tests are looking better and better.
I installed the Mr Cool DIY unit with the pre charger refrigerant lines two years ago and it has been flawless. I have a drop ceiling and left the excess coil length in the ceiling for neater looking installation. It was a breeze to install with a very explicit video on you tube. Almost idiot proof. I keep it set on 66 in winter and 68 in summer and it does great job with the humidity.
Chiming in on pressure test vs vacuum - I have done a bunch of automotive AC work including making my own AC lines. I will say that I have had a number of leaks in my DIY installs that only became apparent after charging the system, but held under vacuum. Slightly different tech but vacuum may tend to pull things together and stop the leak, where pressure might push them apart - if that makes sense.
I am definitely interested in putting a mini split in my garage at some point. I have an electric resistance heater (30A 230V) which works well but burns the $$$ in the winter, and a window AC unit that works marginally (ok up until we are in the mid-90s+) and would like to combine both into one system.
I am definitely interested in putting a mini split in my garage at some point. I have an electric resistance heater (30A 230V) which works well but burns the $$$ in the winter, and a window AC unit that works marginally (ok up until we are in the mid-90s+) and would like to combine both into one system.
I left out another reason someone might skip the nitrogen pressure test and that is time is money. They probably don't want to stand around for an hour or more to see if the pressure goes down. I am in no hurry so I have left it under pressure overnight if I get to that point late in the day.
Just wondering if HVAC professional/expert who installed a unit for him/her self would have to hire another HVAC professional/expert for the plumbing in order to maintain the warranty.
Okay, I'm through with that. Back to the lathe!
Okay, I'm through with that. Back to the lathe!
For anyone thinking about installing a mini split, I learned that they are eligible for a 30% tax credit as part of the 2022 Tax Relief Act.
I belive that there are credits available for the next ten years for all sorts of energy efficient upgrades /purchases.
Here's a link :
www.energystar.gov
I belive that there are credits available for the next ten years for all sorts of energy efficient upgrades /purchases.
Here's a link :
Federal Tax Credits for Energy Efficiency
www.energystar.gov
Dang - missed that by 2 months, ordered my unit the 10/30/21.For anyone thinking about installing a mini split, I learned that they are eligible for a 30% tax credit as part of the 2022 Tax Relief Act.
I belive that there are credits available for the next ten years for all sorts of energy efficient upgrades /purchases.
Here's a link :
Federal Tax Credits for Energy Efficiency
Another Mr. Cool DIY 18k owner. I installed our in a 600 sqft 2-car detached garage with 9' ceilings. It replaced a "portable" AC unit that was loud and didn't work well for cooling and two (in-efficient) radiant cove wall-attached heaters which were quiet, but also very slow to heat. The mini split indoor noise level is *very* low -- just the fan, which is quiet. Outdoor noise level is quiet as well.
I think the new (3rd generation) Mr. Cool DIY units come with a short (2-3 ft) piece of line on the air handler and the rest of the lineset separate for easier installation. I'm not sure if anyone sells it with a shorter lineset though -- 25' is what HD/etc. sell it with.
I think the new (3rd generation) Mr. Cool DIY units come with a short (2-3 ft) piece of line on the air handler and the rest of the lineset separate for easier installation. I'm not sure if anyone sells it with a shorter lineset though -- 25' is what HD/etc. sell it with.
I belive that you can still claim that credit from 2021 retroactively through 2025. The amount then was 10‰ but that is still something... Right?
I belive that the garage door fell under the "exterior door" qualification.
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