Ductless Airconditioner Installation

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iwirehouses

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A buddy of mine is putting in a Ductless Air Conditioner. The unit takes 20amps of straight 220 12/2. It came with 3 pieces of SJ cord, between maybe 20 and 30 feet. Two of the SJ's have green/white/black, the other one has red/yellow/?i can't remeber. The condensor is fed, then 6 conductors go over to the indoor unit. The problem is, there are no knockouts on the indoor unit and the condensor only has 2. How would you guys hook this up?...I'd say, run a carflex whip from the disconnect to the condensor with black, white and green of THHN. From the Condensor, run carflex back to the disconnect with two SJ cord's inside (white,green,black and red, yellow,?). From the disconnect, bring each of the two SJ cords out of their own seperate knockout, using a compression cord connector. Run both SJ's to the indoor unit. Then the third SJ cord that it came with I wasn't even gonna use. I don't see this very practical, but its the only feasable way considering there are only two knockouts for a piece of carflex coming in and two pieces of SJ going out, so maybe bring them out the disconnect instead, where there are more knockouts. The only other way to install this would be to run the whip going in, then conduit straight from the condensor to the indoor unit with 6 THHN conductors in it, and disregard the SJ cord all together. Which way would you do it?

Oh, and anyone know how loud these things are? Are they like a typical central air condensor?
 
iwirehouses said:
A buddy of mine is putting in a Ductless Air Conditioner. The unit takes 20amps of straight 220 12/2. It came with 3 pieces of SJ cord, between maybe 20 and 30 feet. Two of the SJ's have green/white/black, the other one has red/yellow/?i can't remeber. The condensor is fed, then 6 conductors go over to the indoor unit. The problem is, there are no knockouts on the indoor unit and the condensor only has 2. How would you guys hook this up?...I'd say, run a carflex whip from the disconnect to the condensor with black, white and green of THHN. From the Condensor, run carflex back to the disconnect with two SJ cord's inside (white,green,black and red, yellow,?). From the disconnect, bring each of the two SJ cords out of their own seperate knockout, using a compression cord connector. Run both SJ's to the indoor unit. Then the third SJ cord that it came with I wasn't even gonna use. I don't see this very practical, but its the only feasable way considering there are only two knockouts for a piece of carflex coming in and two pieces of SJ going out, so maybe bring them out the disconnect instead, where there are more knockouts. The only other way to install this would be to run the whip going in, then conduit straight from the condensor to the indoor unit with 6 THHN conductors in it, and disregard the SJ cord all together. Which way would you do it?

Oh, and anyone know how loud these things are? Are they like a typical central air condensor?
Click to expand...

You are an apprentice and from what your asking i think this is beyond your ability at this time.Forget this sj cord idea.You said its 220 but your wanting to run blk and white.Ask the journeyman your working under to go with you.In time you will understand.
 
I often encounter ductless split systems in data rooms in schools. Each one is different. The last time I designed one in a building, the mechanical contractor installed a different one than designed around, and didn't notify the electrical contractor. The electrician wired it the way I showed on the prints and burned it up.

You must get wiring diagrams and also heed Jim's advice.

Jim T
 
jtester said:
I often encounter ductless split systems in data rooms in schools. Each one is different. The last time I designed one in a building, the mechanical contractor installed a different one than designed around, and didn't notify the electrical contractor. The electrician wired it the way I showed on the prints and burned it up.

You must get wiring diagrams and also heed Jim's advice.

Jim T
Click to expand...
Wht didn't he read the instructions?
 
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jtester said:
I often encounter ductless split systems in data rooms in schools. Each one is different. The last time I designed one in a building, the mechanical contractor installed a different one than designed around, and didn't notify the electrical contractor. The electrician wired it the way I showed on the prints and burned it up.

You must get wiring diagrams and also heed Jim's advice.

Jim T
Click to expand...
Did the electrician use aluminum wire?
 
From what i am understanding about ductless units they really are nothing more than split unit systems that are just costly.I guess they have some value in situations that running ducts would be a problem and they should be quit.
 
the issue of these units has been on this webb page many times. warning: read the instructions very carefully!!! they are all made in china and the installation instruction was writen by someone who didn't speak english or understand it!!! it is very easy to screw them up --- i know of three different setups. all were different. it will take additional "stuff" to make them comply with our codes.

they are super quiet --- i have two units and never had a problem with them...
 
This is the most common type of ac unit in the 50 th state. The major players here are Mitsubushi, Sanyo, and Fujitsu. All three are pretty reliable. I have 6 mitsubushi units at my house.
 
Just trying to get your opinions if you would run 2 SJ cords out of one knockout in conduit, or if you would just throw out all the cable assemblies they gave you to run straight THHN in conduit (which is what I would do). I learn so much from this forum that I actually thought thats what it was for, sorry. I just figured that you guys would know and it wouldn't be too much trouble to easily increase my knowledge as well. I am one to ask my teacher more questions per day then most do per year. Unfortunatly, there is no class right now.
 
I would not run sj cord. I would use liquid tite flex in exterior locations with thwn, and if it is a dwelling, romex in dry interior locations for the branch circuit feed. And I would also highly recommend using a journeyman electrician or better for helping in the installation.
 
I am not doing the installation, Its just when I get a question in my head, I need it answered or it drives me crazy. The problem is, school has not begun yet.
 
iwirehouses said:
I am not doing the installation, Its just when I get a question in my head, I need it answered or it drives me crazy. The problem is, school has not begun yet.
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I see no reason you could not do the job.Have a journeyman check your work BEFORE it gets turned on.And no do not use that sj cord.Do not count on an inspector that it is correct.This is a lot of money involved and you can fry it in a second if even one wire is wrong.
 
Iwirehouses,

Find the manafactures installation instructions, no matter what kind of

equipment you are dealing with, if the book says" run cord #1 from ------and

terminate--------next, run cord #2----------" that's what I would do.

Follow the manafactures instructions!!!!!!! 110.3(B) it's not a suggestion,

it is the code. Also, if anything "bad" happens and the equipment is wired

real nice but not by the Manf Instr who do you think is going to get the blame.

Think it over. and keep asking questions.
 
charlie tuna said:
the issue of these units has been on this webb page many times. warning: read the instructions very carefully!!! they are all made in china and the installation instruction was writen by someone who didn't speak english or understand it!!! it is very easy to screw them up --- i know of three different setups. all were different. it will take additional "stuff" to make them comply with our codes.
Click to expand...

About 3 weeks ago, my guys installed the wiring for a Mitsubishi's "Mr. Slim" ductless Air Conditioner.

dss_wallmount.jpe


The guy who was running the whole project was trying finish the lighting in the room addition and was running late. So, I sent another jw who had finished his job early to help him. The 1st guy had sort of read the instructions and told the 2nd guy how to run 3 wires.

The condensing unit had terminals marked S1, S2, & S3. Unbeknown to guy 2 is the fact that S1 & S2 are the 240 volt terminals and S2 & S3 are the 12-24volt DC terminals. S2 carries both AC and DC and he swapped S1 for S2 - no workie!

Way too much time is waisted trying figure out the problem. One more look at the instructions, change the two wires, and we got cooling!
 
Minuteman said:
About 3 weeks ago, my guys installed the wiring for a Mitsubishi's "Mr. Slim" ductless Air Conditioner.

dss_wallmount.jpe


The guy who was running the whole project was trying finish the lighting in the room addition and was running late. So, I sent another jw who had finished his job early to help him. The 1st guy had sort of read the instructions and told the 2nd guy how to run 3 wires.

The condensing unit had terminals marked S1, S2, & S3. Unbeknown to guy 2 is the fact that S1 & S2 are the 240 volt terminals and S2 & S3 are the 12-24volt DC terminals. S2 carries both AC and DC and he swapped S1 for S2 - no workie!

Way too much time is waisted trying figure out the problem. One more look at the instructions, change the two wires, and we got cooling!
Click to expand...

You got lucky.Could have just burned up a new A/C.Accidents will and do happen,some very costly.
 
like i said "the instruction manual that comes with these things is garbage"... and i can't understand why even though they are by different manufacturers the manual is very misleading. the last one i installed was for myself!!! and the guy i bought it from told me it was a 240 volt unit. never opened the box -- just wired my garage office for a 240 supply to my a/c outlet. these things install like a picture frame --so i'm about 99 per cent finished when i dig this thing out of the box. something in the instructions mentioned 120 volts and when i looked at the nameplate it showed "120/240 volt(optional)". i surched the cardboard box it came in --- nothing!!! i had other things to do and waited to call this guy i bought it from to confirm it was 240 volts. when i did, he changed his tune and said "wwweeelllll, maybe--just maybe---it could be 120 volts because he had these mixed up with another order. now, i had it wired for 240 but never closed the breaker... i looked through the manual very carefully (which is unusual for me) and could not determine the actual voltage. then went out to the condensor and noticed a small stamp on the outside of the fan motor "120"! thats all that was there---"120". i changed it over to 120 volts and started it up --- ran fine. to me it's like they could use this same instruction manual for either unit since it never specified the voltage.

the units are designed to be installed within ten feet of each other--condensor and evaporator that is. so you have ten feet of suction and liquid refrigerant lines and also the control and power wiring is sj cord and is ten feet long. i have installed them within ten feet and inserted the sj cords into sealtight for protection and i have also installed them where they were more than ten feet apart and had to change out the sj cords to hard wire. i was very sceptical about these units when they first came out --- but they are easily installed--have a decent efficency rating--and no problems. the larger condensor units are narrow and have a high profile which requires some "rigging" to secure against hurricane damage. note: if you install one of these for yourself --- check the voltage closely and connect the liquid line first and purge the suction line real good before connecting it by bleeding freon from the liquid side. the unit has extra gas in it's original charge for this purpose.......
 
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