New DIY Mini Split

I gave up on the used mini split that I installed two years ago and never got the lines to hold a vacuum. Since the temperatures have been in the 90’s almost all summer, we needed air conditioning for a visit from family who are sensitive to heat and I had my eye on the Mr. Cool 115 volt DIY unit for some time. Supply House had a nice sale on them so I bought the 12,000 btu unit which is the only one that is 115 volt. Unfortunately it is not Energy Star rated. Its rating is 17.5 when some mini splits are in the 20’s. But I didn’t have very many choices and the line set is extremely easy to route through the walls and connect as it is pre-charged with refrigerant. So I didn’t have to hook up the vacuum pump and evacuate the lines or clean them with nitrogen or test for the correct amount of refrigerant or any of the complicated things that a mini-split install normally requires.

Mr Cool DIY 12000 btu
Mr Cool DIY 12000 btu

It only took an afternoon to remove the old copper piping and replace it with the new flexible pipe. Getting it through the small hole in the outside wall was the most difficult part. The pipes come with insulation and a heavy vinyl cover. That is what I could not fit through the hole. So I slit the vinyl up to the extent of the pipe I needed to reach the connections. I cut the vinyl off at the hole and took the slit cover outside to rewrap the pipe. Then I taped it with Gorilla duct tape.

Flexible pipe in vinyl sleeve
Flexible pipe in vinyl sleeve and old pipe being removed

I saved the actual connections until the next day when I was fresh. It is important to connect the pipes to the outside unit quickly. Both hands hold the wrenches to turn the pipes nice and tight. After the two connections are made the inside valves are opened with an allen wrench that is supplied and then the pipes are checked for leaks. I had a leak detector as well as a liquid that was supposed to show if gas was leaking but there were no leaks.

The internal unit was also easy to hang. I had the general spot already and just took down the old unit and its back plate and put up the new one. I was able to use studs for the new back plate and wall anchors to hold the bottom. The hole from the old unit was in the right place for the new unit.

Inside unit being installed
Inside unit being installed

It was convenient to be able to work from the top of the refrigerator too. The unit came with plenty of drain pipe. I didn’t run the drain water outside though but to the standpipe for the washing machine. I used some hose clamps to keep the hose running downhill for good drainage.

I had to move the washer and dryer out of the way to run the pipe. It was a good time to empty any lint from the dryer vent. When the electrician was working in the space he had crushed the new dryer vent. I tried to push out the dents but with the new piping there was not enough room for the old vent path. I had to cut back the connecting pipe and reinstall the sections. I screwed and taped them together and bought a new uncrushed semi flexible vent pipe. Reconnecting the dryer vent took as long as the entire routing of the mini split pipes.

Finally I was able to fill in the rest of the hole with expanding foam and tape the inside vapor barrier back in place. The unit comes with silicone putty to seal the pipe but I just used expanding foam outside.

Outside unit
Outside unit information

The startup was super easy using the included remote. Rechecked for any leaks of refrigerant and set the temperature and fan speed. The cool air felt very good inside. Our guests came and went and we kept running the air conditioner. The house holds heat but it also holds cool so this 1 ton unit is adequately cooling the main area of the house. The back bedrooms still get warm though in the high 70’s not 80’s.

The system comes with a wifi usb dongle. I followed the directions to install it in the unit’s cover indoors. Unfortunately I was not able to get the wifi connection to work and I have emailed a tech support request.

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