Ductless Mini Split Wiring

[MNBobcat]

Hi Guys,

I'm installing a ductless mini split this weekend in order to get Air conditioning into a room on the second floor of the home. The location where the compressor unit will be installed outside is directly outside of a totally finished room in the basement. Trying to get wiring out that outside wall for the power for the compressor would be tough.

However, when I did some remodeling in the home I ran a PVC chase tube from the basement to the attic. So getting power from the panel in the basement into the attic will be super simple. My thought was that I could run that power line through the soffit and down the wall to the compressor. I will be using speedi-channel to conceal the mini split line sets, so I could run the compressor power line through the speedi-channel alongside of the line sets.

Does anyone know if there is a code issue with that? I know that code varies from state to state but I'm wondering in general if this is a bad idea. Also, the wire that I would use to run the 220 from the panel to the compressor I'm assuming is going to be similar to a romex in that its encased and not THHN. I know you're not supposed to run anything other than THHN through conduit. My chase tub is 1 1/2" PVC so it shouldn't be a problem with heat or anything.

Thoughts?

 

[frugalangler]

why increase the length of wire for a high current circuit UN-necessarily, find a way to penetrate the wall like thu the sill plate or rim joist in a more traditional manner.

Trying to get wiring out that outside wall for the power for the compressor would be tough.

Tough doesn't equal IMPOSSIBLE!!

 

[wagne223]

I dont see it as problem as long as the wiring is in conduit.......

 

[scdeerslayer]

If you can get to the outside between the panel and that room, or at the panel, what about running conduit around the house near the ground? Then it can be concealed by shrubbery or other plants.

 

[RNeumann]

Hi Guys,

I'm installing a ductless mini split this weekend in order to get Air conditioning into a room on the second floor of the home. The location where the compressor unit will be installed outside is directly outside of a totally finished room in the basement. Trying to get wiring out that outside wall for the power for the compressor would be tough.

However, when I did some remodeling in the home I ran a PVC chase tube from the basement to the attic. So getting power from the panel in the basement into the attic will be super simple. My thought was that I could run that power line through the soffit and down the wall to the compressor. I will be using speedi-channel to conceal the mini split line sets, so I could run the compressor power line through the speedi-channel alongside of the line sets.

Does anyone know if there is a code issue with that? I know that code varies from state to state but I'm wondering in general if this is a bad idea. Also, the wire that I would use to run the 220 from the panel to the compressor I'm assuming is going to be similar to a romex in that its encased and not THHN. I know you're not supposed to run anything other than THHN through conduit. My chase tub is 1 1/2" PVC so it shouldn't be a problem with heat or anything.

Thoughts?

I'm confused. The wire will be run on the inside of the building- through this non conduit conduit. The line set will run on the exterior in speedi-channel. The above is an assumption based on your description.

How does the line set and romex end up together?

 

[MNBobcat]

The power for the compressor would run from the panel in the basement up through a chase tube going to the attic, across the attic and then down through a hole in the soffit and into the speedi-channel. It would exit the channel at the bottom near the ground and hook up to a power shutoff on the outside wall next to the compressor.

 

[Old Red]

You are going to love your new mini split. I have had one for 2 years in my garage. What did you purchase? Are you going to pull your own vacuum or call an HVAC tech to do it for you?

 

[RNeumann]

The power for the compressor would run from the panel in the basement up through a chase tube going to the attic, across the attic and then down through a hole in the soffit and into the speedi-channel. It would exit the channel at the bottom near the ground and hook up to a power shutoff on the outside wall next to the compressor.

The answer to your question about romex in speedi-channel is no. Romex isn't rated for outdoor use and speedi-channel isn't approved for wiring.
Where the romex leaves the structure you will need to add an exterior rated junction box and transition from romex to single wire like the THHN you mentioned above. From the junction box you will need to run down the exterior wall with appropriate conduit (I'm assuming parallel to the speedi-channel and into a disconnect at the compressor. From the disconnect you will need to run outdoor rated flex into the compressor.

To be frank your idea doesn't sound like a good one. The posts above are on point- through the rim joist or conduit near the ground would be a better choice based on my understanding of your description.

Good luck!

 

[MNBobcat]

I found the copper line, that goes from my furnace room horizontal about 12 feet (above the ceiling) and then outside, for my central air. Looks like I could drill a new hole through the wall next to where it comes out and then use a long fish to pull a line from my furnace room to the outside wall so that's what I'm going to do.

Thanks again for all the suggestions.

 

[Rustyiron]

I'm not 100% on this, but I believe that the power for the wall unit comes from the compressor and is included and runs with the "line set" from the compressor to the wall unit(s). Might even be low voltage DC with the "modulating" variable speed fan.
I'm going to install one and am doing the wiring (for the whole addition) this fri., well my cousin is. He's an electrician and told me that for the past 10 years he's only supplied power to the compressor.:confused3:
I'm looking at Mitsu - LG - and another I don't remember.

 

[MNBobcat]

I was talking about power to the compressor.


The wire you're talking about that goes to the wall unit is 14/4

I'm not 100% on this, but I believe that the power for the wall unit comes from the compressor and is included and runs with the "line set" from the compressor to the wall unit(s). Might even be low voltage DC with the "modulating" variable speed fan.
I'm going to install one and am doing the wiring (for the whole addition) this fri., well my cousin is. He's an electrician and told me that for the past 10 years he's only supplied power to the compressor.:confused3:
I'm looking at Mitsu - LG - and another I don't remember.

 

[Rustyiron]

I was talking about power to the compressor.


The wire you're talking about that goes to the wall unit is 14/4

That's what I get for "speed reading":thumbsup:

 

[3Ts]

I've got an 18,000 BTU LG mini-split. The power comes from a 25 amp circuit breaker in the main panel out to the outside unit (compressor) via it's own conduit. On the inside unit, the control wire (14/4) and the copper lines and the drain line come thru the wall in the same conduit. The control wires attach to the compressor near the power lines. There is a single access panel that covers both the power and control cables.

Hope this helps.

 

[MNBobcat]

I bought an LG 24,000 BTU unit today with two 12,000 BTU wall units. I'll do all of the installation but I will leave the hooking up of the line sets at the compressor to an HVAC guy. You can't use a normal flaring tool as they aren't rated for R410. Also I'd like him to pressure test the line and then pull a vacuum on it to purge the air from the lines.

I've got an 18,000 BTU LG mini-split. The power comes from a 25 amp circuit breaker in the main panel out to the outside unit (compressor) via it's own conduit. On the inside unit, the control wire (14/4) and the copper lines and the drain line come thru the wall in the same conduit. The control wires attach to the compressor near the power lines. There is a single access panel that covers both the power and control cables.

Hope this helps.

 

[3Ts]

The mini-splits require a really low vacuum for some reason and I've heard A/C guys who don't deal with mini-splits often will not go as low as they need to. The installation manual will specify what the vacuum reading is and for how long. If I remember right it's down around 300 microns. Be sure they follow the installation manual.

 

[Old Red]

I purchased a Pioneer 1.5 ton unit back in August 2015. It has been running flawlessly so far. They are really nice "cheaper" units. I believe they are an off brand but get lots of good reviews on Amazon.

 

[Rustyiron]

I bought an LG 24,000 BTU unit today with two 12,000 BTU wall units.

Hey Bobcat, do you mind telling us what you paid for the equipment? I'm looking at the same (LG) set up and trying to justify what they want installed.

 

[MNBobcat]

It came to about $3,300.00 with the line sets, drain lines, power lines for the wall units, 36" wall mount for the compressor, 13 feet of speedi channel and a 30 amp box for outside.

 

[3Ts]

You can see prices for mini-splits at supply house.
Mini-Split Air Conditioners, LG Mini-Split Air Conditioners, Comfort Aire Mini-Split - SupplyHouse.com

 

[Tractor Seabee]

In reading through this thread it is apparent the OP is not really knowledgeable enough in either electrical work or refrigeration work to tackle this project as DIY W/O a lot of technical advice. Hope you can separate the wheat from the chaff of all the advice given here or that he has some good friends in those trades.

In my early life as an AC&R technician we would not come into a partially assembled system and complete it. No way to warrant the work ethically. Some guys would go tackle it on their own W/O the bosses blessing. They would virtually reinstall the system to fix all the things done wrong. Those homeowners wound up paying more in the end than if they would have contracted the project to start with. Sears sold home units to the DIY community that had pre-charged lines and pre-assembled electrical harnesses. Should be easy for anyone who can read to install; Murphy's law prevailed; failures were still common and Sears contracted for us to go fix the screw-ups and they ate the cost.

Today I am retired, still have all my equipment, and planning a remote heat pump for my house. Just had a new furnace installed and had the coil installed for the future. I have discussed doing part of the work my self with 3 contractors, they all said "forget it" we will not be involved in something we cannot warrant. All three stated that it was very difficult to get warranty replacements from manufacturers when they are called out on a service call for a failure. Imagine the run around a home owner would get. End of story I will do the concrete slab and the rack to mount the refrig lines and electrical conduit on.

Since HF now sells vacuum pumps, leak detectors and gauges for a couple hundred bucks, every body is now an expert refrigeration technician. Only their 2 stage vacuum pump will get the 5 micron vacuum required to evacuate and dry out a system. It takes a special gauge to read down to 5 microns. (expensive) Their gauges have special connectors on the hoses unique to the auto AC stems and the pressure/temp conversions is probably not for the same refrigerant either.

Refrigeration 101, Ron