EcoRenovator - View Single Post - LG mini-split install project

SparkyAZ · 03-17-12, 06:46 PM

Hi all,

I'm working on an LG mini-spit AC install for my garage/workshop. Last fall I completed the majority of it, pouring a pad, setting the outdoor and indoor unit, and connecting power, lineset, and control wire. Now all that's left is the final leak test, evac, and charge. This was a used unit that came out of service but appears to have been in working order (the price was right for the unit). It was pumped down so the refrigerant should be inside the unit but I have no idea how much is there. Prior to stumbling across this forum, I was going to have a mini-split A/C guy to do the final hookup. That's still on the list - the guy we contract with to do our mini-split A/C at my workplace owes me a callback on Monday. Since we just installed 3 new units at work, I'm hoping they can give me a deal

At any rate, I still would like to get the 'stupid/easy' stuff out of the way so as to not burden the A/C guy with trivial stuff like finding leaks in my first-attempt flare fittings...

A couple questions for the mini-split gurus on this forum, dumb ones first:
- are there any issues with using a small amount of teflon pipe seal compound (pipe dope goo) on the threads of the flare fitting? And by this, I mean on the male threads only so it gets pushed back and away from the fitting by the compression nut, and only a small amount such that it doesn't contaminate the flare face or get inside the fitting. Is there any issue with this compound reacting with the R410a refrigerant? I've used it before on threaded compressed air fittings and threaded plumbing fittings, and it seems to work well once it sets up. I see there is a blue Nylog sealing compound normally used by those in the HVAC trade. I'm not opposed to buying some of the Nylog, it's readily available on ebay. Its just that I don't have any of it now and I do have a tube of the Teflon stuff.

- thoughts on installing an external drier in the lineset? Since this system was pumped down and closed off prior to the lineset being cut and the system moved, I'm hoping there is not any moisture in the system, but I have no way of knowing for sure. This unit was in Arizona all of it's life, and it's pretty dry here. Still, I don't know if there is any other 'crud' in the system that should be filtered out, All I know is there is 'some' refrigerant in there, I have no idea how much or what condition it is in. If I do this, I'll have to buy one as I don't have one. The unit has a 1/4" discharge line, I presume that's where these normally go in-line (based on the photos I've seen on this forum).

The rest of the install looks pretty straightforward from there. I'm going to borrow a N2 tank from a friend who does paintball along with the associated regulators to bring the pressure down to 100~125psi. I will probably have to adapt whatever fitting they have on the output of the regulator to a 1/4" flare, but I suspect I can find the required parts at Home Depot or the paintball store. Then to find/borrow a vacuum pump, buy some vac oil, micron gauge, etc, etc! First things first, though pressure test - no leaks!

03-17-12, 06:46 PM	#1
SparkyAZ Lurking Renovator Join Date: Mar 2012 Location: Arizona Posts: 5 Thanks: 1 Thanked 0 Times in 0 Posts	LG mini-split install project Hi all, I'm working on an LG mini-spit AC install for my garage/workshop. Last fall I completed the majority of it, pouring a pad, setting the outdoor and indoor unit, and connecting power, lineset, and control wire. Now all that's left is the final leak test, evac, and charge. This was a used unit that came out of service but appears to have been in working order (the price was right for the unit). It was pumped down so the refrigerant should be inside the unit but I have no idea how much is there. Prior to stumbling across this forum, I was going to have a mini-split A/C guy to do the final hookup. That's still on the list - the guy we contract with to do our mini-split A/C at my workplace owes me a callback on Monday. Since we just installed 3 new units at work, I'm hoping they can give me a deal At any rate, I still would like to get the 'stupid/easy' stuff out of the way so as to not burden the A/C guy with trivial stuff like finding leaks in my first-attempt flare fittings... A couple questions for the mini-split gurus on this forum, dumb ones first: - are there any issues with using a small amount of teflon pipe seal compound (pipe dope goo) on the threads of the flare fitting? And by this, I mean on the male threads only so it gets pushed back and away from the fitting by the compression nut, and only a small amount such that it doesn't contaminate the flare face or get inside the fitting. Is there any issue with this compound reacting with the R410a refrigerant? I've used it before on threaded compressed air fittings and threaded plumbing fittings, and it seems to work well once it sets up. I see there is a blue Nylog sealing compound normally used by those in the HVAC trade. I'm not opposed to buying some of the Nylog, it's readily available on ebay. Its just that I don't have any of it now and I do have a tube of the Teflon stuff. - thoughts on installing an external drier in the lineset? Since this system was pumped down and closed off prior to the lineset being cut and the system moved, I'm hoping there is not any moisture in the system, but I have no way of knowing for sure. This unit was in Arizona all of it's life, and it's pretty dry here. Still, I don't know if there is any other 'crud' in the system that should be filtered out, All I know is there is 'some' refrigerant in there, I have no idea how much or what condition it is in. If I do this, I'll have to buy one as I don't have one. The unit has a 1/4" discharge line, I presume that's where these normally go in-line (based on the photos I've seen on this forum). The rest of the install looks pretty straightforward from there. I'm going to borrow a N2 tank from a friend who does paintball along with the associated regulators to bring the pressure down to 100~125psi. I will probably have to adapt whatever fitting they have on the output of the regulator to a 1/4" flare, but I suspect I can find the required parts at Home Depot or the paintball store. Then to find/borrow a vacuum pump, buy some vac oil, micron gauge, etc, etc! First things first, though pressure test - no leaks!