# Samsung mini split units



## Shockdoc (Mar 4, 2010)

Podagrower said:


> So, about 23 months ago, I wired a Samsung AQV 18JA mini split unit. Got my money, unit worked fine, everyone was happy.
> 
> Today I get a call that its not working right, and it's my fault. Apparently, I was supposed to run shielded cable for the control circuit from the outdoor unit to the indoor unit. I can not find anything in the manual about what kind of wiring needs to be run between the two units.
> 
> ...


I just roughed in for one and the supplier supplied 14/7 CT cable, I have seen hack HVAC contractors run 14/4 SJ between units, in the past i have run 12/4 romex.


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## robnj772 (Jan 15, 2008)

Podagrower said:


> So, about 23 months ago, I wired a Samsung AQV 18JA mini split unit. Got my money, unit worked fine, everyone was happy.
> 
> Today I get a call that its not working right, and it's my fault. Apparently, I was supposed to run shielded cable for the control circuit from the outdoor unit to the indoor unit. I can not find anything in the manual about what kind of wiring needs to be run between the two units.
> 
> ...


What do they mean by shielded cable? I usally don't run the wire for the control circuit,the HVAC guy does but they always run 14/3 rx for it.


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## Podagrower (Mar 16, 2008)

robnj772 said:


> What do they mean by shielded cable? I usally don't run the wire for the control circuit,the HVAC guy does but they always run 14/3 rx for it.


For the mini splits, somehow the cabling between the outside unit and inside unit has become the electricians problem in our area. I don't mean standard thermostat wiring. After you land the 208 at the outdoor unit, you need to take 208, and 2 or 3 other wires (depending on the unit) to the indoor unit. The 2 or 3 wires are varying voltages.


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## heartlessmcfly (Nov 7, 2010)

From my understanding, and I may be wrong, but the cabling from outside in is done in 14ga with 3 conductors. I've seen it done with 14/3 romex 99% of the time sleeved thru carflex. And isn't the voltage converted to DC on the indoor unit?


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## robnj772 (Jan 15, 2008)

heartlessmcfly said:


> From my understanding, and I may be wrong, but the cabling from outside in is done in 14ga with 3 conductors. I've seen it done with 14/3 romex 99% of the time sleeved thru carflex. And isn't the voltage converted to DC on the indoor unit?


Yea,that is what is done around here.


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## voltz (Jun 2, 2010)

heartlessmcfly said:


> From my understanding, and I may be wrong, but the cabling from outside in is done in 14ga with 3 conductors. *I've seen it done with 14/3 romex 99% of the time sleeved thru carflex*. And isn't the voltage converted to DC on the indoor unit?


...NM romex is not rated for wet locations even if installed in rigid conduit and sealtite


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## TOOL_5150 (Aug 27, 2007)

voltz said:


> ...NM romex is not rated for wet locations even if installed in rigid conduit and sealtite


If I wire my outdoor speakers with romex, did I create a code violation?

~matt


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## Shockdoc (Mar 4, 2010)

The "thhn" inside romex is the same "thhn" wire that is in MC. Who's to say that stripping back the plastic sheath and installing a transition to where romex enters the outside relm is not code compliant?


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## voltz (Jun 2, 2010)

Shockdoc said:


> The "thhn" inside romex is the same "thhn" wire that is in MC. Who's to say that stripping back the plastic sheath and installing a transition to where romex enters the outside relm is not code compliant?


thhn is not rated for outdoor use, thwn is. See table 310.13(A) look up thhn and look under the application provisions column 08 code page 142

As side note, often the wire is dual rated thhn/thwn, you have to check


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## kbsparky (Sep 20, 2007)

Conductors inside of romex are not labeled, nor are they dual-rated.


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## Shockdoc (Mar 4, 2010)

voltz said:


> thhn is not rated for outdoor use, thwn is. See table 310.13(A) look up thhn and look under the application provisions column 08 code page 142
> 
> As side note, often the wire is dual rated thhn/thwn, you have to check


It's hard to say or prove anything since 9 out of 10 times, the conductors inside MC and NM cables are unmarked. On a sidenote, I just ran 14/3 NM in PVC to an outdoor ceiling fan mounted under a deck. Where is water going to enter my conduit system? Yes in the old days of sleeving EMT with sill plates I can see the need for UF use but certain applications should not require a transition to UF. I do't know of any inspector who will drop my fan to ensure I used UF anyway, the don't even open up devices on me.


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## Shockdoc (Mar 4, 2010)

kbsparky said:


> Conductors inside of romex are not labeled, nor are they dual-rated.


They are the same that is used in MC, strip open both cables and compare. Question is, what type of conductor is it?


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## robnj772 (Jan 15, 2008)

Ok well I only stated that the HVAC guys use 14/3,When I have to run that particular wire I use UF 

BUT

The rx in a wet location is a different debate and isn't going to solve the OP's problem.


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## ampman (Apr 2, 2009)

Shockdoc said:


> I just roughed in for one and the supplier supplied 14/7 CT cable, I have seen hack HVAC contractors run 14/4 SJ between units, in the past i have run 12/4 romex.


 12/4 romex i've never heard it called that


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## Shockdoc (Mar 4, 2010)

ampman said:


> 12/4 romex i've never heard it called that


12/4 w ground, 14/4 w/ ground , red,white, black, blue and bare ground. Lately the stock has been white black, red, wht/red tracer w/ bare ground. Where have you been ?


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## Shockdoc (Mar 4, 2010)

robnj772 said:


> Ok well I only stated that the HVAC guys use 14/3,When I have to run that particular wire I use UF
> 
> BUT
> 
> The rx in a wet location is a different debate and isn't going to solve the OP's problem.


 The 14 CT cable that came with my current install is a good product to use. Now here is a question, Inside unit is over 6' in hieght off floor, does it require a disconnect below 6'. I have gotten two sides to this one, I personaly wire it straight from the outside unit.


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## heartlessmcfly (Nov 7, 2010)

I've never put a means of a disconnect on the indoor unit


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## bobelectric (Feb 24, 2007)

Does the abreviation rx mean nm/romex?


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## TOOL_5150 (Aug 27, 2007)

bobelectric said:


> Does the abreviation rx mean nm/romex?


I am betting so, because it is so hard to type romex - or nm

~Matt


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## Midnitel (Feb 21, 2009)

Nobody mentioned that romex has paper liner inside.
This on was under house soak and wet.


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## macmikeman (Jan 23, 2007)

Midnitel said:


> Nobody mentioned that romex has paper liner inside.
> This on was under house soak and wet.


The picture you posted leads me to believe that the wire in question had other problems than some water wicking up into the sheath. The water may have contributed to the problem, but I am quite sure it didn't cause it. Ive seen romex direct buried for over a decade, running sump pumps with no damage to the sheath, or the internal conductors once it had been uprooted. Don't take the fact that I am posting this info to mean I endorse runnning it in wet locations, I am just reporting fact.


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## Podagrower (Mar 16, 2008)

So, it turns out it doesn't matter what kind of wiring you use if the condensor fan motor is broken and the compressor is shutting off on high pressure/overamperage.

3 hours OT, plus material. Cha-ching.


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## ampman (Apr 2, 2009)

Shockdoc said:


> 12/4 w ground, 14/4 w/ ground , red,white, black, blue and bare ground. Lately the stock has been white black, red, wht/red tracer w/ bare ground. Where have you been ?


 well thank you captain obvious i knew what he was talking about


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## robnj772 (Jan 15, 2008)

Shockdoc said:


> 12/4 w ground, 14/4 w/ ground , red,white, black, blue and bare ground. Lately the stock has been white black, red, wht/red tracer w/ bare ground. Where have you been ?


Why the extra conductor? You got your 2 hots and a ground for power and the 3 control terminals with anouther ground. Why would you run 4 wire.

That 12/4 you are talking about is for home runs the red with white tracer is to accomidate MWBCs and AFCIs....


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## Shockdoc (Mar 4, 2010)

MY HVAC guy requested it.....Give em what he wants....He's paying for it.


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## Kdubya (Jan 2, 2011)

*think electronics*

you guys are getting confused, the original question was regarding shielded cable to connect the interior mini split to the outdoor condensor

I installed some LG Artcool heat pump mini splits and the manual said I should use 18-4 to connect the interior unit to the exterior. This cable supplies power to the interior units as well as communication. The sensitive electronics involved in the communications are subject to electronic noise. I was going to use sprinkler wire but the tech support for LG told me that that may cause problems down the road. I ended up using shielded 18-4 stranded security cable. Works great. 

To answer the other question, I don't see how it can be the electricians fault if he used the recommended wire had I not asked I would have used the sprinkler wire which according to the manual would have been fine.

One other thing to know, the line sets (tubing from inside unit to outdoor unit) can be purchased with line set covers. My inspector told me that as long as my wire was inside the line set cover (which it was as it was strapped to the tubing bundle) he considered it inside a conduit.


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## jwjrw (Jan 14, 2010)

heartlessmcfly said:


> I've never put a means of a disconnect on the indoor unit



The inside unit also needs a disconnect within sight.


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## mdfriday (May 14, 2007)

The one I have done the cable that goes between the condenser and the blower was provided with the unit. They are pretty easy to install, but they do see a bit "cheeply" manufactured. Could be anyones guess as to what is wrong.

They may just be trying to put the blame on you, since it is always the electricians fault.


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## Mr. Sparkle (Jan 27, 2009)

I've wired up a few that came with a cut of 14/4 SJ for between the units, I just sleeve it.


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## McClary’s Electrical (Feb 21, 2009)

heartlessmcfly said:


> I've never put a means of a disconnect on the indoor unit


 


And every time you did it wrong.


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## robnj772 (Jan 15, 2008)

Kdubya said:


> you guys are getting confused, the original question was regarding shielded cable to connect the interior mini split to the outdoor condensor
> 
> I installed some LG Artcool heat pump mini splits and the manual said I should use 18-4 to connect the interior unit to the exterior. This cable supplies power to the interior units as well as communication. The sensitive electronics involved in the communications are subject to electronic noise. I was going to use sprinkler wire but the tech support for LG told me that that may cause problems down the road. I ended up using shielded 18-4 stranded security cable. Works great.
> 
> ...


I think your confused. The units we are talking about have an inside unit that takes 110 between 13-20 amps so how the hell can you use 18-4?


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## HARRY304E (Sep 15, 2010)

Podagrower said:


> So, about 23 months ago, I wired a Samsung AQV 18JA mini split unit. Got my money, unit worked fine, everyone was happy.
> 
> Today I get a call that its not working right, and it's my fault. Apparently, I was supposed to run shielded cable for the control circuit from the outdoor unit to the indoor unit. I can not find anything in the manual about what kind of wiring needs to be run between the two units.
> 
> ...



If it is not in the manual that you must use shielded cable how would you be responsable ..

If the info is not in the manual how are you suposed to Know that?


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## Podagrower (Mar 16, 2008)

Hey, I wraped this one up back at post 23. Evap fan no worky. Unit shut down on high head pressure. AC guy big stupid. Pay me now.


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## Cletis (Aug 20, 2010)

*mini*

"I think your confused. The units we are talking about have an inside unit that takes 110 between 13-20 amps so how the hell can you use 18-4?"



That's weird. The ones we just did we ran 12-4 THHN in conduit just to be safe on available power. It turns out they only run on about 100V from condensor into the unit and the signal wires. And the unit only draws 1.5 amps (Blower) 

In our case we could of 14-4 min but I though you can't run anything under 14 for 100 V items?


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## Dennis Alwon (May 9, 2009)

Cletis said:


> "I think your confused. The units we are talking about have an inside unit that takes 110 between 13-20 amps so how the hell can you use 18-4?"


Some units are powered at the outside unit with 14/2 but the inside units are low voltage. The ones I have done require more than an 18 awg wire.


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## Kdubya (Jan 2, 2011)

*mini splits wiring*

All the LG Artcool's use 18-4 shielded stranded cable to connect the inside to the outside. I have an HVAC contractor who is going exclusively to the Mitsubishi mini split and he uses 16-4 stranded not shielded. Mitsu says that as long as the wire is stranded the "noise" doesn't affect the communications.

To wire the outdoor unit I used 10-2 because the breaker recommended is a 25 amp. 

All mini splits I have dealt with are the inverter type so it is possible the wiring for those and the non-inverter type are different. 

I am only relating what I was told by the factory techs regarding the shielded cable. There is no reason to use shielded cable if all you are doing is supplying power to the indoor unit.


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## McClary’s Electrical (Feb 21, 2009)

Kdubya said:


> All the LG Artcool's use 18-4 shielded stranded cable to connect the inside to the outside. I have an HVAC contractor who is going exclusively to the Mitsubishi mini split and he uses 16-4 stranded not shielded. Mitsu says that as long as the wire is stranded the "noise" doesn't affect the communications.
> 
> To wire the outdoor unit I used 10-2 because the breaker recommended is a 25 amp.
> 
> ...


 
Nothing wrong with overkill, but you could have got by with #12 on that one


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## 220/221 (Sep 25, 2007)

I've never heard of shielded cable for this type of installation. I do know that these things suck. Trying to install them to be code compliant is always an issue.






Shockdoc said:


> The "thhn" inside romex is the same "thhn" wire that is in MC. Who's to say that stripping back the plastic sheath and installing a transition to where romex enters the outside relm is not code compliant?


 
This comes up as often as ground up/down and taping wirenuts and nothing ever changes. 

1) It's illegal, get over it. 

2) It's a safe installation, get over it.


My arguement never changes either. "Outside" doesn't necessarily equal "normally exposed to wetness"


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## SmithBuilt (Jan 9, 2009)

Kdubya said:


> I have an HVAC contractor who is going exclusively to the Mitsubishi mini split and he uses 16-4 stranded not shielded.



Mitsu's instructions say min 14 ga 600 volt rated wire. 

I'm not sure why you would need the 4th wire. I normally use 14/3 w/grd. 




Kdubya said:


> Mitsu says that as long as the wire is stranded the "noise" doesn't affect the communications.


That's a new one to me. I would like to know if there's any proof to that. Sometimes those so called Tech's don't know as much as they would like you to believe.


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## BigCrapper (Dec 5, 2010)

I had that problem before. I thought since thhn/THWN(most wire is duel rated) was rated for 600 volts I can put control and power in the same conduit. Figured that insulation would be impervious to induction or interference. I was wrong. Easy fix is to run an 18/3 shielded outdoor rated jacket with the lineset. Wire is a little pricey though but labor saving.


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