Garage Mini Split Installation Debrief

[Foreman05]

Hey everyone,

I know people appreciate follow-up posts after installs to help with their own DIY projects, so I figured I'd share my experience.

Location: Central Kansas
Garage: Attached
Size: 1,184 sq. ft.
Layout: L-shaped
Ceiling Height: 10 ft.
Insulation: R-13 walls, R-38 ceiling
Garage Doors: 12' and 16', both insulated
Interior: Finished drywall
Air Sealed: Yes

Mini Split: Pioneer Diamante Pro (Model WYT024GLS120RL) – 24,000 BTU, 21 SEER2
Vacuum Pump: XtremepowerUS 1/4 HP (Model 71093) — don't forget the adapter.
Line Set Cover: DuctlessAir 14'

Over the past year, I think I reached the end of YouTube and the internet researching mini splits before finally working up the courage to install one. HVAC isn't really in my wheelhouse, but I'm fairly handy. The only part that really made me nervous was pulling the vacuum and releasing the refrigerant.

I had the electrician install the disconnect when our house was built, so the electrical side was straightforward aside from connecting the whip. Even with the breaker off and the disconnect pulled, I was still convinced I was going to end up like the cat in Christmas Vacation. Thankfully, everything turned out to be much easier than I expected.

I chose the Pioneer because the price was right ($1,350 on sale at Home Depot), it appears to have good parts availability and support, and the warranty seemed solid. I seriously considered the MrCool DIY since it's recommended so often, but after buying a vacuum pump and adapter for about $135, I still came out roughly $250 ahead once I sell the pump. I also ended up with a higher-efficiency unit. Pioneer actually has very good installation instructions, and after reading through them once and following along, the process was surprisingly straightforward.

The installation took me about 13 hours from start to finish. That included a two-hour pressure test, a one-hour Harbor Freight run for crow's-foot wrenches, and watching Pioneer’s 30-minute installation video twice. If you're not an overthinker like I am, I honestly think this could be a solid 6–8 hour project.

I waited a few days before installing the line set cover just to make sure everything was operating correctly. I mounted the indoor unit right at the bend of the "L" so roughly one-third of the airflow feeds the long, narrow section while the remaining two-thirds cools the main 36' × 24' area. So far, it's worked out extremely well.

Verdict: Do it.

The biggest surprise was how much humidity was in my garage. I had no idea until this thing started pulling water out of the air. At one point I measured nearly a liter per hour during the initial cool-down.

I keep the garage set at 78°F during the summer. The inverter is fantastic—it loafs along at low speed most of the time and ramps up when one of the big doors opens, which happens often since our 16-foot garage door has basically become the family's front door. I will post back with power consumption, I will say last month went up from the previous month $30 but, it also was way hotter so the house unit was working harder as well.

When I'm planning to spend time working in the garage, I drop it to about 74°F, and I've found myself out there a lot more simply because it's comfortable now.

This has easily been one of the best upgrades I've made to the garage.

If you're nervous about pulling a vacuum, don't be. Looking back, it really isn't as intimidating as it seems. You still have to make the same flare connections regardless of which system you buy. The difference is that with a traditional system, the refrigerant stays sealed inside the outdoor unit until you're ready to release it. Pulling a vacuum removes air and moisture from the lines and lets you verify your flare connections are leak-free before opening the service valves. Once I understood what was actually happening, the process made a lot more sense.

Anyway, hopefully this helps someone who's on the fence. Feel free to ask if you have any questions, and thanks to everyone here who unknowingly answered mine while I was researching.

Lastly, I'd be remiss if I didn't give a shout-out to my pal ChatGPT. It was a real lifesaver in a few areas throughout this project!

 

[loganb]

Nice write up! Also had similar surprise with how much better it felt with just lower humidity and the same temp! Now enjoy the **** out of it... you'll need it this coming week!

 

[Overboost44]

That is a really great write up and good to know the 24k works well in there.

I will have 900sq ft and plan to use a 2 zone, 24k in the main garage with another 12k in the upstairs man cave. My only problem with doing it so inexpensively (like you did) is that my county requires a permitted HVAC professional to do the install and I have yet to find anyone that will pull a permit and let me do it myself.

 

[Foreman05]

Appreciate it!

I work for a general contractor, my recommendation would be to find a subdivision that’s being built in and talk to the HVAC guys. They most often work for a company but hold the license themselves and don’t mind the side hustle cash.

This goes for most of the trades tbh, hope it works out for you.

 

[67King]

If you're nervous about pulling a vacuum, don't be. Looking back, it really isn't as intimidating as it seems. You still have to make the same flare connections regardless of which system you buy. The difference is that with a traditional system, the refrigerant stays sealed inside the outdoor unit until you're ready to release it. Pulling a vacuum removes air and moisture from the lines and lets you verify your flare connections are leak-free before opening the service valves. Once I understood what was actually happening, the process made a lot more sense.

I just did a Cooper & Hunter 9,000BTU in my attic (12" open cell foam, so very well insulated). Had my contractor run condensate and refrigerant lines, as well as control and power, so mine was easily plug and play. Oh dear lord it feels heavenly up there now, even set at 80 degrees, because of the humidity difference.

I did not know the system came pre-charged. Darn near destroyed my vacuum pump when I went to evacuate it. Which brings me to a question.......how do you evacuate the system when the unit comes precharged?

 

[Foreman05]

For my unit, the refrigerant is in the outdoor unit, so when the vacuum is pulled, it’s on the line set and the indoor unit. The outdoor unit until you open those valves to let the refrigerator out is self-contained.

 

[67King]

For my unit, the refrigerant is in the outdoor unit, so when the vacuum is pulled, it’s on the line set and the indoor unit. The outdoor unit until you open those valves to let the refrigerator out is self-contained.

The only port on mine was on the low pressure valve. Open to evacuate, and you simultaneously opened the refrigerant to the rest of the system (and vacuum pump).

I should have just opened it, and purged some on the high pressure side (system off) the same way you do gauges, by cracking that flare fitting loose, befire opening that high pressure valve. But I didnt thibk of that until it was too late.

 

[fitter30]

I just did a Cooper & Hunter 9,000BTU in my attic (12" open cell foam, so very well insulated). Had my contractor run condensate and refrigerant lines, as well as control and power, so mine was easily plug and play. Oh dear lord it feels heavenly up there now, even set at 80 degrees, because of the humidity difference.

I did not know the system came pre-charged. Darn near destroyed my vacuum pump when I went to evacuate it. Which brings me to a question.......how do you evacuate the system when the unit comes precharged?

Valves at the condenser are shipped closed. After lines are connected most manufacturers want 500-600 lbs of nitrogen pressure for 4 to 8 hours. Nitrogen is blown out, vacuum to under 500 microns. Install manual will list what the manufacturer wants. With a unit in a deep vacuum unit valve are opened. Vacuum pump is pulling te vacumm through gauge manifold and can be valved off.

 

[JunkBonds]

Mini splits are da bomb.

I did my garage 3 years ago. It has worked fine down to -22c.

 

[67King]

Valves at the condenser are shipped closed. After lines are connected most manufacturers want 500-600 lbs of nitrogen pressure for 4 to 8 hours. Nitrogen is blown out, vacuum to under 500 microns. Install manual will list what the manufacturer wants. With a unit in a deep vacuum unit valve are opened. Vacuum pump is pulling te vacumm through gauge manifold and can be valved off.

These directions only listed instructions for recharging, not initial setup. But yes, I know the preferred method. The bigger problem is that the service hookup didn't give access to either the lines to the evaporator or the condenser. See Attached from the manual. The red arrow is the service line hookup. The valve is the setscrew like thing. You can see how it closes the two sides simultaneously.

 

[manwithtools]

The only port on mine was on the low pressure valve. Open to evacuate, and you simultaneously opened the refrigerant to the rest of the system (and vacuum pump).

I should have just opened it, and purged some on the high pressure side (system off) the same way you do gauges, by cracking that flare fitting loose, befire opening that high pressure valve. But I didnt thibk of that until it was too late.

You need to RTFM and not mislead folks how installing minisplits is done. The OP has it perfectly explained.

You don't open the valve to the condenser to evacuate the lines. You evacuate the lines and the indoor unit to the required vacuum level, seal up the system and then release the refrigerant from the condenser unit into the lines and indoor unit. All most all mini splits work the same way.

 

[Foreman05]

Yes, my condenser unit had the connection for the line set and had an alan screw to release the refrigerant as well as another connection for my gauge set and vacuum. As I am not an HVAC guy the whole thing is gibberish, but between YouTube and my manual it was pretty straightforward.

 

[Foreman05]

 

[manwithtools]

Yes, my condenser unit add the connection for the line set an And Alan had screw to release the refrigerant as well as another connection for my gauge set and vacuum. As I am not an HYes, my condenser unit add the connection for the line set an And Alan had screw to release the refrigerant as well as another connection for my gauge set and vacuum. As I am not an HVAC guy the whole thing is gibberish, but between YouTube and my manual it was pretty straightforward.

You have described it perfectly, no need to defend your approach to another poster who clearly did not read the manual.

BTW, thank you for your detailed description of the process. I now wish I had done the same for the two Mitsubishi Hyperheat units I installed last year.

 

[67King]

You need to RTFM and not mislead folks how installing minisplits is done. The OP has it perfectly explained.

You don't open the valve to the condenser to evacuate the lines. You evacuate the lines and the indoor unit to the required vacuum level, seal up the system and then release the refrigerant from the condenser unit into the lines and indoor unit. All most all mini splits work the same way.

Hey, man, look. I can't tell you how many times I RTFM trying to figure it out. And like I said, I had no idea it was pre-charged, which may have what led to all the confusion. I was expecting to evacuate not just the lines and evaporator, but the condenser as well. Also, go back and re-read, I was ASKING, not telling anyone.

It took no time to get down, like instantly. Maybe because my pump is for vacuum bagging composites and abotu 10 times larger than is necessary, but it did not appear to be pulling a vacuum on the system, I would have expected it to not immediately bottom out the gauge, but rather several seconds or a couple of minutes. Every car I've done has been the same way.

So it appears that the service port goes around the valve and passes to the lines. That is what I was trying to figure out. OP's picture looks exactly like mine, and it didnt' appear to me that the valve worked that way (and honestly, from the outside, it still doesn't).

 

[67King]

You have described it perfectly, no need to defend your approach to another poster who clearly did not read the manual.

BTW, thank you for your detailed description of the process. I now wish I had done the same for the two Mitsubishi Hyperheat units I installed last year.

There is no need to be a jackhole to a guy who is asking questions.

 

[manwithtools]

There is no need to be a jackhole to a guy who is asking questions.

It wasn't clear you were asking a question with your follow on posts. Sorry to upset you, just don't like misinformation left in an informative thread like this.

Maybe this will help: https://media.cooperandhunter.us/2809/Installation-Manual.pdf

Also, you need the proper AC vacuum pump to reach the recommended evacuation levels.

 

[manwithtools]

So it appears that the service port goes around the valve and passes to the lines. That is what I was trying to figure out. OP's picture looks exactly like mine, and it didnt' appear to me that the valve worked that way (and honestly, from the outside, it still doesn't).

The service port does not go around the valve. When shipped, the valve is closed. You evacuate the lines and indoor unit via the service port with the valve closed, then you seal up the service port and next open the valve to release the refrigerant to the system.