LG Mini Split Install

estoppel101 · 07-08-16, 12:22 AM

Howdy all,

I live in Nebraska and I am a huge DIY guy as my dad luckily taught me a lot of skills. I am currently tackling a dual zone mini split by LG. I came across a link on this forum where Xringer was discussing a LG mini split install back in 2010. I found it very helpful as the manual is still not updated in 2016 to reflect the design of their two way gas/liquid valves with schrader ports. As a result, I am confused how to conduct the nitrogen test and vacuum test. I was hoping you could help me. My questions are:

1. When conducting the nitrogen pressure test on the LG system, which has the two valves (one for gas and one for liquid) each with a schrader port, do I hook the blue nitrogen line from the manifold to just one valve or do I use the redline as a second conveyance from the manifold to the other port as well? The manual is so bad it says connect lines to both valves but the picture shows only the blue side connected. If I connect to both valves will nitrogen flow over the top of the schrader port in both valves pressurizing the whole system from both directions at once?

2. When conducting the vacuum test, I have the same question. Do I connect just the blue line and close the other valve off totally or do I create a loop vacuum by using both the blue and red lines from the manifold with a micron gauge in the loop somewhere?

Any information would be greatly appreciated.

oil pan 4 · 07-10-16, 01:59 AM

I am going to say do both at once due to valves, the compressor and such.
Vacuum it, nitrogen charge, vacuum again then add the charge.
I want to install a split. Normally I don't work on systems this small. Usually what I work with has from 70lb to 30,000lb of refrigerant.

jeff5may · 07-10-16, 07:31 AM

Some tips on purging and evacuating pretty much any type of split system:

1: Most important: do not disconnect any service hoses while they are under vacuum! Atmospheric air will leak in, contamination will result.

2: To speed evacuation, both lines (red and blue) can be connected. Two hoses suck gas better than one. Make sure and close both ports on the manifold gauge when vacuum is achieved.

3: install a flare tee fitting on the center hose of the manifold gauge. Run one side of the tee (using a hose) to the vacuum pump, the other side to the charging cylinder. Again, always end up with pressure inside the hoses before disconnecting anything.

4: use a micron vacuum gauge if at all possible. The dial gauges are no good at reading deep vacuum levels.

estoppel101 · 07-11-16, 11:59 AM

Appreciate the responses. Every detail helps. Been self studying on the net. Surprisingly, some tech schools will post video lessons on YouTube. This help but can't ask questions. Saw this forum and everyone seems to be pretty cool about helping. The HVAC forums not so much.

estoppel101 · 07-14-16, 06:18 AM

Quote:

Originally Posted by jeff5may

3: install a flare tee fitting on the center hose of the manifold gauge. Run one side of the tee (using a hose) to the vacuum pump, the other side to the charging cylinder. Again, always end up with pressure inside the hoses before disconnecting anything.

That is a great tip. I have been concerned about moisture getting back into the lines when I complete the process of releasing the vacuum. The manual just says not to allow too much time from vacuum release to charging. Their instructions struck me as a little incomplete. I was planning on breaking the vaccum with nitrogen.

I came across some good information in an online textbook sample which I did not see anywhere else on the web or in the manual. The service valves on a mini split look like normal HVAC service valves but internally they are designed differently. That has been the source of some of my confusion. I have watched numerous training videos on the web and they all relate to regular service valves. But according to a text book they are not. Here is the language:

Most new residential split systems come equipped with unit
installation valves, as shown previously in Figure 25-4. These
valves are used to hold the refrigerant charge in the outdoor
unit while it is shipped. These valves have three ports: the
port to the unit, the line port, and the Schrader valve service
port. Even though they have three ports, they do not behave
like standard manual service valves. No ports are closed in the
back seat position; the Schrader valve service port is always
open to the line port regardless of the position of the valve.
These valves are used primarily for holding the system
charge during shipping. The systems are shipped with the valve
run all the way down clockwise, Figure 25-18. After connecting
the refrigerant lines and indoor coil, the system is evacuated
through the service port. The valve is turned counterclockwise
to open it and allow the trapped refrigerant to flow through-
out the system. Typically the valve is never used again because
it does not control refrigerant flow to the service port.

Fundamentals of HVAC; Stanfield, Carter.

jeff5may · 07-14-16, 06:55 AM

^^This is why you always want to tightly cap all service ports with a cap that has a good o-ring in it. If the schrader valve ever decides to leak, there is a redundant seal in the cap.

estoppel101 · 07-14-16, 07:30 AM

Quote:

Originally Posted by jeff5may

^^This is why you always want to tightly cap all service ports with a cap that has a good o-ring in it. If the schrader valve ever decides to leak, there is a redundant seal in the cap.

If the factory supplied service caps do not have an o-ring inside, can a person add one or would that not allow the cap to seat on the threads low enough thus creating more risk of leak?

estoppel101 · 07-21-16, 04:53 PM

Thanks for the kind comments. Installation appears to be successful so far. High pressure test revealed no leaks at 550 psi. Kept system for 24 hours and there was no loss once temperature change was calculated. The vacuum triple evac was more challenging. Initially tried to get to 500 microns with the manifold hoses for my final deep vac but no dice on my final draw. Just as everyone says those hoses are not meant for a deep vacuum. Went to all copper lines. Wow. Between drying the system with nitrogen twice before and changing to copper lines, reached 500 microns in 15 minutes. Held it there for two hours and brought back to atmosphere with nitro. Charged the lines by opening the service lines and all worked.

pelotin · 08-06-16, 07:05 PM

I was doing my second MS installation just at the very same time you were doing your LG, I installed a Daikin 9K btu for my home office and I was able to vacuum down to 69 microns, I had another Daikin installed last Feb by a "technician" and I think I did a better job than this professional. Last June I installed a LG 12K for my TV room and on that one I was able to vacuum down to 88 microns. Wow LGs mini splits blows cold air, colder than my Daikins.

Thank you

mejunkhound · 08-07-16, 12:43 AM

I was able to vacuum down to 69 microns

what kind of setup do you have to get down to 69 microns?

07-08-16, 12:22 AM	#1
estoppel101 Lurking Renovator Join Date: Jul 2016 Location: Papillion, NE Posts: 6 Thanks: 1 Thanked 0 Times in 0 Posts	LG Mini Split Install Howdy all, I live in Nebraska and I am a huge DIY guy as my dad luckily taught me a lot of skills. I am currently tackling a dual zone mini split by LG. I came across a link on this forum where Xringer was discussing a LG mini split install back in 2010. I found it very helpful as the manual is still not updated in 2016 to reflect the design of their two way gas/liquid valves with schrader ports. As a result, I am confused how to conduct the nitrogen test and vacuum test. I was hoping you could help me. My questions are: 1. When conducting the nitrogen pressure test on the LG system, which has the two valves (one for gas and one for liquid) each with a schrader port, do I hook the blue nitrogen line from the manifold to just one valve or do I use the redline as a second conveyance from the manifold to the other port as well? The manual is so bad it says connect lines to both valves but the picture shows only the blue side connected. If I connect to both valves will nitrogen flow over the top of the schrader port in both valves pressurizing the whole system from both directions at once? 2. When conducting the vacuum test, I have the same question. Do I connect just the blue line and close the other valve off totally or do I create a loop vacuum by using both the blue and red lines from the manifold with a micron gauge in the loop somewhere? Any information would be greatly appreciated. Last edited by estoppel101; 07-08-16 at 08:17 PM..

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07-10-16, 01:59 AM	#2
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	I am going to say do both at once due to valves, the compressor and such. Vacuum it, nitrogen charge, vacuum again then add the charge. I want to install a split. Normally I don't work on systems this small. Usually what I work with has from 70lb to 30,000lb of refrigerant.

07-10-16, 07:31 AM	#3
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	Some tips on purging and evacuating pretty much any type of split system: 1: Most important: do not disconnect any service hoses while they are under vacuum! Atmospheric air will leak in, contamination will result. 2: To speed evacuation, both lines (red and blue) can be connected. Two hoses suck gas better than one. Make sure and close both ports on the manifold gauge when vacuum is achieved. 3: install a flare tee fitting on the center hose of the manifold gauge. Run one side of the tee (using a hose) to the vacuum pump, the other side to the charging cylinder. Again, always end up with pressure inside the hoses before disconnecting anything. 4: use a micron vacuum gauge if at all possible. The dial gauges are no good at reading deep vacuum levels.

07-11-16, 11:59 AM	#4
estoppel101 Lurking Renovator Join Date: Jul 2016 Location: Papillion, NE Posts: 6 Thanks: 1 Thanked 0 Times in 0 Posts	Appreciate the responses. Every detail helps. Been self studying on the net. Surprisingly, some tech schools will post video lessons on YouTube. This help but can't ask questions. Saw this forum and everyone seems to be pretty cool about helping. The HVAC forums not so much.

07-14-16, 06:55 AM	#6
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	^^This is why you always want to tightly cap all service ports with a cap that has a good o-ring in it. If the schrader valve ever decides to leak, there is a redundant seal in the cap.

07-21-16, 04:53 PM	#8
estoppel101 Lurking Renovator Join Date: Jul 2016 Location: Papillion, NE Posts: 6 Thanks: 1 Thanked 0 Times in 0 Posts	Thanks for the kind comments. Installation appears to be successful so far. High pressure test revealed no leaks at 550 psi. Kept system for 24 hours and there was no loss once temperature change was calculated. The vacuum triple evac was more challenging. Initially tried to get to 500 microns with the manifold hoses for my final deep vac but no dice on my final draw. Just as everyone says those hoses are not meant for a deep vacuum. Went to all copper lines. Wow. Between drying the system with nitrogen twice before and changing to copper lines, reached 500 microns in 15 minutes. Held it there for two hours and brought back to atmosphere with nitro. Charged the lines by opening the service lines and all worked.

08-06-16, 07:05 PM	#9
pelotin Helper EcoRenovator Join Date: Aug 2016 Location: Riverside, CA Posts: 31 Thanks: 11 Thanked 1 Time in 1 Post	I was doing my second MS installation just at the very same time you were doing your LG, I installed a Daikin 9K btu for my home office and I was able to vacuum down to 69 microns, I had another Daikin installed last Feb by a "technician" and I think I did a better job than this professional. Last June I installed a LG 12K for my TV room and on that one I was able to vacuum down to 88 microns. Wow LGs mini splits blows cold air, colder than my Daikins. Thank you

08-07-16, 12:43 AM	#10
mejunkhound Apprentice EcoRenovator Join Date: Apr 2011 Location: PNW Posts: 197 Thanks: 0 Thanked 47 Times in 31 Posts	I was able to vacuum down to 69 microns what kind of setup do you have to get down to 69 microns?