Installed Mini Split, Is my Vacuum set up correctly?

08-22-15, 10:10 PM

Hi, I've been checking out this forum for a while and it gave me courage to install my first mini-split. The quotes I got for the installation were ridiculous. I splurged and got the Mitsubishi Mr. Slim 24k. I got everything set up and went to vacuum out the system today but I can't get the micron gauge to read below 25000 microns. Im sure I hooked it up wrong. The vacuum pump is a 5cfm. The micron gauge is a CPS VG200. The line sets are Mitsubishi 15ft. The hose is a Yellow Jacket 29983 Plus II 1/4" Hose with Compact Ball Valve. Here are 2 pics of my setup. Can you please help me out. If I close the valve to the vacuum pump the microns jump back up. Is that suppose to happen or do I have a major leak? I checked my line sets and all looks well. I also use Nylog on my connections.
tinypic.com/m/ivir09/3
tinypic.com/m/ivir0j/3

Sorry, I don't have enough posts yet to post pictures. Links are above

jeff5may · 08-23-15, 09:16 AM

Looks like u have a leak somewhere. Double check your flare connections. if you still have a vacuum leak after checking, a pressure test with some soapy water will find your leak. If the leak ends up being inside a unit, that's what warranties are for. If the leak is at a bad flare on the line set, it is easier to reflare the pipe end than seek replacement.

This assumes you have the vacuum pump and gauge connected correctly and have followed the install manual included with the unit.

08-24-15, 04:00 PM

Thanks so much jeff5may, you were right. I went back and checked my flare connections and the one right by the unit was the culprit. I disconnected it, set it back with some nylog and tightened it back up. I didn't have nitrogen to do a pressure test, but I did vacumm the lines to about 95 microns. It settled at around 140 and went up to 220 in 15 minutes. Is that a bad thing? Hope not, I was so excited that I opened up the valves and the unit is blowing nice and cold right now. Thanks again for your advice.

jeff5may · 08-24-15, 06:05 PM

220 microns is not bad at all. Whether or not it will hold you will soon find out. If luck is on your side, the system will run great for years. I'm crossing my fingers for a job well done.

08-22-15, 10:10 PM	#1
nuffstylez Guest Posts: n/a	Installed Mini Split, Is my Vacuum set up correctly? Hi, I've been checking out this forum for a while and it gave me courage to install my first mini-split. The quotes I got for the installation were ridiculous. I splurged and got the Mitsubishi Mr. Slim 24k. I got everything set up and went to vacuum out the system today but I can't get the micron gauge to read below 25000 microns. Im sure I hooked it up wrong. The vacuum pump is a 5cfm. The micron gauge is a CPS VG200. The line sets are Mitsubishi 15ft. The hose is a Yellow Jacket 29983 Plus II 1/4" Hose with Compact Ball Valve. Here are 2 pics of my setup. Can you please help me out. If I close the valve to the vacuum pump the microns jump back up. Is that suppose to happen or do I have a major leak? I checked my line sets and all looks well. I also use Nylog on my connections. tinypic.com/m/ivir09/3 tinypic.com/m/ivir0j/3 Sorry, I don't have enough posts yet to post pictures. Links are above

08-23-15, 09:16 AM	#2
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	Looks like u have a leak somewhere. Double check your flare connections. if you still have a vacuum leak after checking, a pressure test with some soapy water will find your leak. If the leak ends up being inside a unit, that's what warranties are for. If the leak is at a bad flare on the line set, it is easier to reflare the pipe end than seek replacement. This assumes you have the vacuum pump and gauge connected correctly and have followed the install manual included with the unit. Last edited by jeff5may; 08-23-15 at 10:21 AM..

08-24-15, 04:00 PM	#3
nuffstylez Guest Posts: n/a	Thanks so much jeff5may, you were right. I went back and checked my flare connections and the one right by the unit was the culprit. I disconnected it, set it back with some nylog and tightened it back up. I didn't have nitrogen to do a pressure test, but I did vacumm the lines to about 95 microns. It settled at around 140 and went up to 220 in 15 minutes. Is that a bad thing? Hope not, I was so excited that I opened up the valves and the unit is blowing nice and cold right now. Thanks again for your advice.

08-24-15, 06:05 PM	#4
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	220 microns is not bad at all. Whether or not it will hold you will soon find out. If luck is on your side, the system will run great for years. I'm crossing my fingers for a job well done.