I am installing 3 mr slim indoor units to be connected to the outdoor unit. I will be running my interconnects up the side of this slab two story into the attic and across attic down opposite outside wall into the rear of my three units. Specs call for three interconnect wires with ground. Do I need two break all three at a disconnect next to the inside unit? Ugly? They do not make three pole residential snap switches. Also any recommendations on the type of cable would be helpful. Each run is approx 150 feet from outdoor unit to indoor unit. Both units are 250 volt with out neutral. my outdoor unit will be fed with a 12/2 from an AC disconnect switch attached to a 200 amp panel.
mr slim
- Thread starter 9934
- Start date
- Status
- Location
- Massachusetts
Yes, and try using a 3 pole manual motor starter. It is not exactly like a normal switch but they are close.
You don't have to use the ugly enclosure, you can put them in a 4" square with a plaster ring and use a normal plate.
480 .... Mr Slim is a Mitsubishi split system.
Then it must be a regional thing. I've never laid eyes on anything other than photos of them.
- Location
- Massachusetts
Be glad, I think they stink as far as the wiring.
From the panel you run a circuit to the outdoor unit, from the outdoor unit to the indoor unit you run a 3 conductor cable that ends up having two hots, a single DC control wire and a ground in it.
The space to land this at the indoor unit is the size of a golf ball.
So they're like mini electric furnaces? An A/C line set for cooling, and toaster strips for heating?
- Location
- Massachusetts
I have not seen any with heat but that sure does not mean they are not available. I see these used a lot in small computer / server / phone rooms.
The power from the outdoor unit powers the indoor fans and the DC lead calls the outdoor unit on when the T-stat calls for cooling.
I have to admit they are nice units as far as cooling, they are very quiet and have some pretty high BTU ratings.
- Location
- Massachusetts
Page 4 of this pdf has the wiring diagram
http://www.mrslim.com/UploadedFiles...09-17_Install_SG79Y952H01-ENGLISH_6-13-07.pdf
http://www.mrslim.com/UploadedFiles...09-17_Install_SG79Y952H01-ENGLISH_6-13-07.pdf
cadpoint
Senior Member
- Location
- Durham, NC
Yes, and try using a 3 pole manual motor starter. It is not exactly like a normal switch but they are close.
You don't have to use the ugly enclosure, you can put them in a 4" square with a plaster ring and use a normal plate.
I thought it was 6 wire's, two A/C, three travelers and a Ground ?
I used a two pole single throw blade switch (rated) breaking the hot and the neutral at the source of A/C and my inspector asked me to take it out ! ??? He said that I only needed a single blade for the hot the unit was a 120V A/C
device.
Now this was brought into the job by the client and not part of the contract documents and I never saw the Tech sheets of this.
I thought I was doing the right thing in this case because of the low voltage side that seems from the illustration of the
device that the neutral could be DC Ground and thus my thought of Breaking it with a 2 pole...
I talked to too different HVAC Tech's about these units both were 65 / 35 negative on their comments of this device.
The over riding statement was the total price verse to the cooling power was not cost effective.
If they had applied a larger / better HVAC design it would not have been required at all. Now in this one situation I think it became an after thought oh we have a Tele comm room space, and the room Calc's dictated this application.
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