24V split unit AC

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Pierre C Belarge

Pierre C Belarge

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Westchester County, New York
I have come across a new type of split unit installation, the first time I have seen one.

The condensor outside is 208v and supplies the split unit inside of the building. There are 5 conductors that are supplied from the outside condensor to the wall mounted unit inside. There is a set of conductors (part of the 5 conductors I mentioned) that supply 12v for the control and another set that supplies 24v for the fan.

I am curious, as I tried to figure this out myself and coming up with a big ?mark. Does the inside wall mounted unit require a separate disconnect?
 
Since the condenser is the power source for the inside unit I would not think you would need a disconnect? You should run this by the manufacturer.
I do understand your question from a safety concern. That repairs and or maintenance for the inside unit must be disconnected from the condenser disco outside or the breaker in the panel.
I also have never seen this type of unit.
There is a new type of room ac that has the condenser and evaporator both outside in one enclosure. (As seen on TV) Then it is just piped up and into the room.
 
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I'll admit I am not sure of the answer. I have wired some of these units and I did not install a switch for the indoor unit. Passed inspection so that makes it ok right? :wink:
 
I took a look at the diagrams for this unit. It does not show any disconnect in the diagram for the inside unit and there is no language that is such as: Check local laws for disconnecting means requirements.

Again, I am not sure... I could not locate in the NEC any special requirements and it just seems odd. Maybe an old dog is going to learn a new trick...:cool:
 
I have run into this a couple of times. Still not sure.

I consider the indoor part an appliance. The units I wired did not have heat strips, therefore I followed 422.31 and 422.32. And did not install a disco inside.

I would like some other opinions on this though.
 
tom baker said:
But does the inside unit require a 15 or 20 ampere, 125 V recepetacle? Per 210.63
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They do not require "line voltage".

The ones I have done are actually fed with 120v to the outdoor condenser. The indoor unit was 24v run from the condenser.
 
:roll: As electricians (in the Broad Sense) we bring service to the device. Our work is reviewed (hopefully) for proper fulfillment of the installation requirements to power up the device(s) for proper service per its requirements.

I know I always have 50 questions anytime I work around much less install any odd equipment, and usually read the manual (if available) at Lunch.
Frankly it?s not our job to worry how it works, its ?Listed?, or how it?s wired inside its ?Listed?. It does not seem to have two sources of voltage, its self contained so no dual service label is required. As I read the OP.

Eighty percent of our work is standard operating practice, ten percent more is checking the requirements due to various extraneous oddities of the installation and the last ten percent is working within the bounds of the AHJ/NFPA-70, contract, etc ? The later ten percentage should have already been clarified before conduit, service is worked anywas. I've even had a friend say it was ninty percent mondan or SOP.

My main point is we work off of listed / approved, equipment, and we protect the electrical service to that point.
Maybe I'm saying the wrong word, listed, but I do look for the UL label seal.
 
Those "mini-splits" that get the power for the indoor unit from the outdoor unit are a total UL listed assembly. No extra disco necessary for that indoor unit when using the factory multi-conductor interconnecting cable.


Now, then, there are some mini-splits in which you just run a field supplied UF cable from terminals on the outdoor unit to power the indoor unit. In my opinion, this does require a disco for the indoor unit. A flush snap-switch will suffice.
 
Marc,
You hit it on the nose. To add a little to mini-splits, they are popular on remods. An outside compressor has the capacity to feed 4 rooms(depending on capacity size) each within 50 feet of unit. rbj
 
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Pierre, I am interested in this unit. Was it a Korean brand? I did one a few months back that was 24 v or 32 volt for the fan (can't recall which). My trusted AC contractor friend told me that it is the best machine he's sold or installed yet. The name of the unit also eludes me. Think it was just some letters.
 
Mac ,,

I am not sure but one of the two do ring the bell to me

One is Hatchi ,

The other one is Samberg [ not sure if spelling is correct ]

I think i might know the third one i think it called ND [ not sure how ya pronouce this long word ]

I did see few unit like what ya describing it pretty instering set up

and the unit is pretty quiet on low speed ya sometime ya not know it was allready running

Merci , Marc
 
The AC man told me it has been on the market about 6 months...it was the first I had seen. I will get the manufacturer's name next time I am there. The outside unit is also smaller than most I have seen before, again the AC guy said they are very quiet and very efficient.
 
macmikeman said:
The name of the unit also eludes me. Think it was just some letters.
Click to expand...

The ones I have seen have been the Sanyo, Carrier, Feeders and Samsung units. Very efficient if you don't mind having the large fan control fastened to the wall in the middle of the room.

They are pretty quiet also.

40qn.jpg
 
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Pierre C Belarge said:
I have come across a new type of split unit installation, the first time I have seen one.

The condensor outside is 208v and supplies the split unit inside of the building. There are 5 conductors that are supplied from the outside condensor to the wall mounted unit inside. There is a set of conductors (part of the 5 conductors I mentioned) that supply 12v for the control and another set that supplies 24v for the fan.

I am curious, as I tried to figure this out myself and coming up with a big ?mark. Does the inside wall mounted unit require a separate disconnect?
Click to expand...
how is the 24 volts connected to the fan many fans have a plug type disconnect built right into the fan unit to service or replace the fan dont forget the condensate pump if the unit is at or below floor level. The pumps are often 240 to utilize the feed from high volt fan coil units . A simplex outlet cord connected pump would suffice. Dont forget the service outlet either if one is not nearby.
 
Ok, I didn't work as hard today so my hard drive isn't as fogged up. The brand was named NG or something similar to that. I believe it is a Korean outfit that get's its fingers into lots of different revenue forms besides air conditioners. But I wire all sorts of foreign brands. That bugger was the quietest condensor I ever came across. The hands down loudest one in my own opinion experience was a brand made in Israel that requires 7 control wires between the condensor and the fan coil unit. I won't say the name and remain a nice guy.
 
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