Some simple mini-split installation questions

[aunsafe2015]

Installing a Mitsubishi hyperheat 9k unit in the next week or two. Having an HVAC guy do the pressure test, vacuum, and initial turn on, but I'll probably do the rest.

1) Mitsubishi calls for a 3" hole and wall sleeve. What are people using for the sleeve, and where are you buying it? Any problem just using a plain old PVC pipe as the wall sleeve? Is a full 3" required or could I get by with 2 or 2.5? Lineset for the 9k unit is 1/4 and 3/8.

2) Does your drywall have to be up before you mount your wall plate? I tore down drywall to install foam insulation. I suppose I could put up a few square feet of drywall just where I plan to mount the wallplate, but it will be a few weeks before I get drywall back up over the entire wall, and I'd rather get the mini split up and running before then...

3) Any problem mounting the wall plate to a 2x8 header above a window? I will not drill the lineset hole though the header but can the rest of the plate be mounted on/screwed into the header?

Thanks!

 

[yeldogt]

they make sleeves -- some sell kits.

look at a few videos -- some installers set blocking and a small section of drywall up to mount the unit ... that's what I did. I made all the seams floating and used floating drywall jointers to make all the seams go away.

In a garage it's less important ...

 

[Lonnies Performance]

I bought these.

https://www.comfortgurus.com/1293-through-the-wall-thimbles

 

[aunsafe2015]

I bought these.

https://www.comfortgurus.com/1293-through-the-wall-thimbles

Which side goes on the exterior wall? The square?

The picture just showing the lineset makes it look like it would be a tight squeeze if you also had a condensate drain line going through...

 

[Saltpeter]

I just installed a 2 Ton Trane mini split. There no need for a sleeve, once the hole is made, run your hoses through it, then I sealed it up with spray foam. The line kit cover covered everything.

My dry wall was already up.

Make sure you leave enough space above the inside unit, don't install it too close to the ceiling, mine called for a 6" clearance.

I'm cooling and heating 1100 Sq Ft. It works awesome, and less than half the cost of a traditional system.

 

[Fixin'Stuff]

1) My Mr. Cool 18K has insulated 1/4, 1/2 and the drain tube. All fit fine through the 2.5 inch hole called out in the instructions. My lineset kit also came with a plastic sleeve to line the hole.

2) I mounted just enough drywall to get the unit mounted on the wall, as I didn't want to mess with it twice. Also, you really can't move it once the lineset is attached. Now I can work on the rest of the drywall without sweating my *** off.

3) I don't see why you couldn't install to the header, if you have enough space above. It just needs to be mounted solidly.

 

[Lonnies Performance]

Which side goes on the exterior wall? The square?

The picture just showing the lineset makes it look like it would be a tight squeeze if you also had a condensate drain line going through...

I bought the one with a square on both ends. Easily fit a 5/8" & 1/4" copper, a 1/2" conduit & a 1/2" drain line.

Plus they come with 2 foam inserts to seal everything.

 

[aunsafe2015]

Awesome replies. Thanks everybody.

 

[PoorOwner]

The sleeve make things complicated, you are required to drill the outside hole at lower elevation and the sleeve don't account for that. I have seen installers drill 2.5" hole and just seal up the outside hole well, no sleeve.

With a sleeve, when you put the unit thru there is a good chance the "bundle" will be stuck and force the sleeve to slip outside and you won't be able to easily push it back in, you will need to redo everything, but it is up to you.

 

[Fixin'Stuff]

The sleeve make things complicated, you are required to drill the outside hole at lower elevation and the sleeve don't account for that. I have seen installers drill 2.5" hole and just seal up the outside hole well, no sleeve.

With a sleeve, when you put the unit thru there is a good chance the "bundle" will be stuck and force the sleeve to slip outside and you won't be able to easily push it back in, you will need to redo everything, but it is up to you.

I had zero problems installing the sleeve that came with mine. It was a somewhat flexible plastic that was easy to trim to fit the angle. Leaving out the sleeve around here could result in water dripping inside the wall. My entire lineset gets condensation on the outside. The insulation just isn't thick enough to prevent it. On some really humid days, even the lineset cover is wet.

 

[PoorOwner]

I had zero problems installing the sleeve that came with mine. It was a somewhat flexible plastic that was easy to trim to fit the angle. Leaving out the sleeve around here could result in water dripping inside the wall. My entire lineset gets condensation on the outside. The insulation just isn't thick enough to prevent it. On some really humid days, even the lineset cover is wet.

The lineset insulation that comes with the chinese machines are substandard. (less than the 1/2" that is recommended) But I had no sweating thru those insulation in california.

The OP doesn't have wall and insulation, so he will be able to foam or insulate thickly around the penetration after mounting even without a sleeve.

 

[Ohmthis]

A 2.5” hole will be fine. Use a sleeve like what is shown, trim to fit the angles needed. A good line set with 1/2” insulation or wrap them in a piece of aramflex (the insulation around standard split system piping) is a must in very humid locations. I wrap them (especially if running through an unconditioned space like an attic or crawl space) with great results. DO NOT use the factory flares on the line set, make new ones (the factory flares are known for being done incorrectly and will leak). Look in the installation instructions, you will be given specs to how close you can mount the head to a ceiling or wall. Put up a piece of drywall first and then mount it. When finishing the rest of my the walls and/or ceiling, shut the unit off and wrap a trash bag around it. They DO NOT filter that well and you will fill the coil and fan with construction dust and will require a partial tear down for proper cleaning.

 

[Fixin'Stuff]

But I had no sweating thru those insulation in california.

Around here, everything is wet, pretty much every morning. Current temp, at 4:15 AM is 75, humidity is 89%, dew point is 75. This isn't even a really muggy morning. I was quite surprised to see the entire length of the lineset cover wet with condensation the morning after installation.

 

[eddieK]

I had zero problems installing the sleeve that came with mine. It was a somewhat flexible plastic that was easy to trim to fit the angle. Leaving out the sleeve around here could result in water dripping inside the wall. My entire lineset gets condensation on the outside. The insulation just isn't thick enough to prevent it. On some really humid days, even the lineset cover is wet.

There is no reason to use a sleeve unless you are exceptionally ****. Cut the hole, route the pipes, make sure the drain is not pinched and has fall. Fill the hole from the outside with steel wool and seal outside with duct sealant. Install cover.

 

[brewchief]

The new insulation we are getting now is a much tougher foam with an outer shell, a 1/4" line is about 2" in diameter by itself and it doesn't compress much.

I just did a 2 head 24k daikin, 2 9k heads with the option to add a third, both were on inside walls and needed condensate pumps. We ended up with a little more then 2 days into it when you figure in the time the homeowner had us doing other parts of the project.

Personally I hate dealing with a lineset buried in the wall, going straight out the back much better.

Given the situation I would pick the location for the unit, locate the lineset hole and then add blocking where needed to secure the unit especially near the hanging points at the top and the latches at the bottom, then drywall and mount the unit.

 

[Ohmthis]

The new insulation we are getting now is a much tougher foam with an outer shell, a 1/4" line is about 2" in diameter by itself and it doesn't compress much.

I just did a 2 head 24k daikin, 2 9k heads with the option to add a third, both were on inside walls and needed condensate pumps. We ended up with a little more then 2 days into it when you figure in the time the homeowner had us doing other parts of the project.

Personally I hate dealing with a lineset buried in the wall, going straight out the back much better.

Given the situation I would pick the location for the unit, locate the lineset hole and then add blocking where needed to secure the unit especially near the hanging points at the top and the latches at the bottom, then drywall and mount the unit.

Brewchief, are referring to the white insulation? That type is water and UV resistant, which you probably already know.

 

[brewchief]

Brewchief, are referring to the white insulation? That type is water and UV resistant, which you probably already know.

Yes, we've had two different versions, one with a smooth exterior and one that was textured, I've only seen it for mini splits so far but I've heard that we will have to use it for all installs in the not to distant future, aside from the larger diameter I like it.

 

[justinjoyal]

We never use a sleeve. No use for that..

2.5in hole is fine for all mini-splits in my experience.

Make sure you stuff insulation around the lineset once it’s in place (if needed) and then seal it up real good with spray foam, then caulking for a clean seal/clean job.

 

[samkumar]

Learning quite a bit from you all here!

 

[aunsafe2015]

Ordered the mini split, line set, etc. from ecomfort today. I bought a 2.5" wall sleeve but may end up simply not using it. I'd rather have it in case I do want it for some reason.

Hopefully everything will arrive this coming week and I can get this up and running next weekend. Very excited to finally see one of these operate in person!

 

[Ohmthis]

Yes, we've had two different versions, one with a smooth exterior and one that was textured, I've only seen it for mini splits so far but I've heard that we will have to use it for all installs in the not to distant future, aside from the larger diameter I like it.

Our mini-split line sets are like that (white with texture), but still using armaflex for standard split. I really like the white stuff, it’s much more resistant to tearing. I hear you on the large diameter, but with 3/4” insulation on our split line sets, everything is large now. I just did a job that required a 1 1/8” suction line. I could barely get the whole thing through a 3” wall sleeve.

 

[yeldogt]

The white covering is what I was told is now required -- to protect the insulation. In some states it must be further protected.

Also == there are special sleeves for air sealing -- they have an additional rubber boot.