Mini Split A/c Disconnects.

mdshunk

This post relates to the HVAC equipment known as a "mini split" or "highwall" unit. The compressor sits outside, same as normal, but the indoor unit is a long narrow unit that hangs on the wall inside. I insert this image for reference:



I did one of these the other day, no differently than the hundreds of others I've done. The branch circuit goes to a field installed weatherproof disconnect outdoors next to the condensing unit. A field installed whip goes from the disco to the outdoor unit. A factory provided multiconductor tray cable is field installed to connect the outdoor unit to the indoor unit. Some of the conductors in this factory supplied multi conductor cable provide power to the indoor unit. If any of you guys have installed any mini splits before, you well know how they're connected.

Well, inspection on Tuesday. I wasn't around, but the equipment was already commissioned and running, so it wasn't a big deal. New inspector dings me for 422.31,32 (2002), with the comment "no disconnect for indoor unit". Holy cow. I guess he's right, but the outdoor unit disco is lockable, and also kills the indoor unit when it's off. Any suggestions on how to approach this? I am certain I could call my regular inspector and he'd over rule this guy and pass it, but perhaps the new guy is onto something.

What do you guys think?

ATS

I think it would be an unnecessary expense. As you said, the outdoor unit provides this function. I've never seen a mini-split with a separate disconnect for the indoor unit. I'd get it over-ruled if I were you, it's hard enough to be profitable without wasting time and material due to an overzealous inspector.

Double-A

We ran into this for a split system we installed last year. The inspector bought off on the exterior disco, if we put a label on the unit cover (plastic shroud, not connection cover) saying where the disco was.

__________________
"My clients’ wishes are the center of my attention." -- David Guido, a contractor in Woodstock, N.Y.
New York Times, July 20, 2006

mdshunk

Well, it won't cost me any much time. Hey, I'm all for doing things to the letter, as long as I know that it's just. If I need to have the branch circuit stop at a double pole snap switch indoors before proceeding to the outdoor disconnect, that's fine. I just want to pin down whether this is a just ruling. Just because I've installed a bajillion of these without a hitch, does't mean that I was doing it right all this time. The fact that this particular inspector dinged me doesn't mean I'm doing it wrong, either.

voltamp

The unit out side also locks out the controller. Its that easy.

DaveTap

I agree that the outdoor disconnect qualifies, but worst case scenario labels and a breaker lock in the panel are faster and cheaper than installing a 2 pole switch, besides its really annoying to come for a service call when their children turn off the switch by the indoor unit... LOL

Sparky Joe

Didn't look at the refference posted, but I'd say his problem is "within sight"?

I did the first one of these a year ago and ran #12's to the outside disconnect and then field installed #14's to the blower inside, though I didn't see in any fuses where the 14's connected in the compressor.

I felt pretty unsure about doing it like this, but the manual said that's how it's done, and the HVAC guy didn't have a clue about anything other than his control wires. Hell of the two units side by side he couldn't even tell me which blower came off which compressor.

SmithBuilt

I've installed several of these lately. Every time I've checked the code to be sure I havn't missed anything.

The only thing I could find is 422.31(B) I'm just refering to the indoor unit. For appliances over 300 va (I would assume there is strip heat in the indoor unit) a lockable disco is ok.

Then there's 422.32 I would have to check but I don't think the small blower is over 1/8 hp. Therefore 422.32 wouldn't apply.

Any comments?

FYI I've installed disconnects on the indoor units I've installed.

kpi

If the inspector is persistent, a nice and ugly 3P (some of the fan coils have 3 ungrounded conductors) motor rated switch surface mounted right next to the fan coil will do the trick.

SmithBuilt

I hate to admit it kpi, but thats exactly what I've been installing. Theres just no way to make it a neat installation.

Super Dave

talk to the heating guys you will probably void the warranty on the unit if you hook it up any other way than what is spec us the point with the inspector it is ul listed to be controlled from the outside disconnect only should win