LG Mini Split Multi Zone questions the manuals and equipment conflict on.
New to the group. Hope this isn't to long as it's going to have 4 issues. This may require someone in the LG install business of someone who has gone down these roads before. I installed 3 separate single zone LG's before, but this is wacky town. Thanks in advance for reading and a big thanks if you have solid answers. Like real life experience.
Moved from "The Main Wall"
1st Issue.
Installing a 3 and 4 zone system both with LG Red 36k OU's and wall mount IU's. One has a 3 port CDU and the other a 4.
In the Submittal on the OU, they say the min. length of the liquid and vapor lines should to both be 16'-4" from IU to CDU and CDU to OU. A/C wholesalers where I got them sells 15' line sets or longer with these complete kits. The IU's have a a stub out of the copper pair of about 20" in length that you fold out from under the unit and pass though the wall. Do I add that 20" to my 15' line set to come up with the min. 16'-4" or do I need 16'-4" on top of the 20" stub. Manual doesn't say and when calling LG tech, they didn't know but suggested to play it safe and add another foot and a half of line. I wasn't impressed with his knowledge. He didn't know the wall units had a stub out. Sheesh. I would rather not have a welded connection. I don't think the cassette version IU's have a stub out so you can't use a 15' foot line set?!? You buy a 25 and throw 40% of it away? Doesn't make common sense.
2nd Issue.
Seller (A/C Wholesalers) doesn't sell (not sure why but suspect liability) the wiring between units. They just say buy a 18 gauge 5 conductor wire from any place like Amazon. Reading the manuals, I have seen it state 18 gauge 5 conductor, elsewhere in the manuals, it says 2 / 14ga. for the power and and 2 / 18 ga. for communication. What?!?! Which is correct and or which is safe to run. I have the 18/5 ran, but wonder if I need to swap the power lines to 14ga. Thoughts?
3rd Issue.
The CDU Manual states that Side B on the unit must be on the top of facing up. Yet with illustrations they show it in various positions with a (correct) next to it and a couple with (incorrect) next to it. Some of the "correct" seem to show the unit on it's side. That would be easier in my situation, but I don't know it's it will work on it's side since they say side B MUST be on the top.
4th and last Issue.
The CDU has a big sticker near the inlet port pairs that states ROOM A, ROOM B, ROOM C and D on my 4 zone. I "thought" when I opened the cover to get to the terminals to connect the power supply and comm. lines from the IU's I would see terminals marked ROOM A, B and so on. NO. Nothing of the sort. Just a block of 8 terminals for the power and 8 for the comm. They say which wire to connect, but not which room it is. Picture above of that. Also on my 3 zone, which pair of terminals do I not use since it's equipped for 4 zones worth of terminals.
In the manuals, it says something to the effect of be certain you connect the power and comm. lines to the correct ROOM the copper is going to, but how do you do that when it's not marked? Does it have some technology where it figures it out itself? Or this just another case of the manual lacking info or the CDU lacking markings.
It also looks like the yellow terminal block has a white wire going from 3A to 4B on the 8 terminal block. 3A should go to 3A. If that marked correctly, then that's wrong isn't it? Is the sticker upside down? The power side sticker isn't and it looks correct.
If the answers were in the manuals, I would of have this install much further along already.
Comments
-
-
1, lineset minimums are the min length of field installed lineset. by CDU I'm assuming you mean branch box or commonly called BDU. Yes the listed minimums from ODU-BDU and BDU-IDU are 16.4 feet. Pro's are typically buying lineset in 100' lengths where I am at, so they cut what they need. these should not be treated as a "kit" install typically you need professional knowledge to install them
2, for the R32 units you need code compliant power cable for the power, that would e 14 ga wire, for communication you can use 18ga wire. You can't run your high voltage power through 18ga wire. Rectorseal sells an all in one wire for this called duckt-strip, this is the most annoying part imo, when all else fails just run 2 lengths of 14-4 wire and you have extra wire, its cheaper than the ducktstrip. you can run 16ga comm wire but it must be shielded, I would also shield the 18ga wire, 14ga unshielded is relatively common. in defense of your seller, they don't sell the wire because they didn't know. Nobody knew LG changed their multi's to a 5-wire and when I say nobody I mean not even LG USA knew about it until around 8 months after they were in the market.
3, go with the "good example" shown in the install manual, some of the verbal descriptions in this manual seem to suffer from poor translation.
4 wiring the branch box is a little confusing. it shouldn't matter which block of terminals go to which IDU though, for consistency I would go from left to right, first power goes to 1st unit, 1st comm goes to 1st unit. This will get set with the pipe addressing step on install which you are going to love. If any of your IDU did not come with a wireless remote controller (air handler for example) then ask your wholesaler about this stat, which you will almost certainly need for the pipe addressing step. Also just ask them now to get the pipe addressing instructions, when you do post them here because they are missing a step. and DO NOT AUTO address unless its well over 50f outside.
thermostat for accessing pipe addressing on AHU or units without a remote controller
PREMTB101 (in white or black, can disconnect when done)
and to defend your seller once again nobody knew about the pipe addressing thing until very recently either. They never told anyone about it just a few tech support people. High up sales guys didn't even know about it, some still don't
0 -
Might be too late, but by the sounds of it you are doing a wall mount per room setup with a multisplit. Unless this is very carefull sized (both ODU and IDU), these systems don't work well. There is even a Mitsubiship app note specifically about going down this route.
What works well is a couple of larger ducted unit on multi. Again, sizing is still important but much easier than wall mounts.
Since it is not fully installed, might be a good time to re-evaluate before it becomes a very expensive replacement down the road.
0 -
Yes, I realized I should of posted in the AC grouping. Thank you for all the information. I spent a half hour on the phone with LG today. This guy was more knowledgeable then last weeks, but had to go ask someone else on most of these questions. Your answers agree with his btw.
Older units did run 18/4 on the wiring he said.
He did say that I need to swap the two wires going to the yellow block in the CDU. They are wired wrong (or you could say the sticker is wrong).
I'll request the addressing info and post.
Again, thanks for taking the time to reply. Much appreciated.
0 -
I had heard that some of the branch boxes were stickered wrong from the factory but hadn't seen it myself yet. should have mentioned that above.
0 -
Categories
- All Categories
- 87.3K THE MAIN WALL
- 3.2K A-C, Heat Pumps & Refrigeration
- 61 Biomass
- 427 Carbon Monoxide Awareness
- 119 Chimneys & Flues
- 2.1K Domestic Hot Water
- 5.8K Gas Heating
- 114 Geothermal
- 165 Indoor-Air Quality
- 3.7K Oil Heating
- 76 Pipe Deterioration
- 1K Plumbing
- 6.5K Radiant Heating
- 395 Solar
- 15.6K Strictly Steam
- 3.4K Thermostats and Controls
- 56 Water Quality
- 51 Industry Classes
- 50 Job Opportunities
- 18 Recall Announcements