More Mr. Slim Questions ???

[FlowerFarmer]

Hey all,

So I'm going to bite the bullet and get a 36k Mr Slim Split so that I can build out a proper 8k room.

I've got a few questions. I've been looking at the units from goductless ..they have 2 listed however

Mr. Slim 34,600 BTU 15.1 SEER Single Zone Ductless Mini Split

Mr. Slim 36,000 BTU 14.5 SEER Heat Pump Single Zone Ductless Mini Split

Which one do I want? The 34k is cooling only. The 36k has a heat pump. Do I want the heat pump model since I'll be running it in a climate that experiences winters 20-30F somtimes down to single digits?

Also..
The unit only seems to include the indoor, outdoor, remote, and mounting plates for the indoor unit. So to be clear I'll needing the following accessories.

Lineset - Indoor unit will be close to outdoor unit so 15' should be adequate however I've heard the units are pre-charged for 25' (i think). Does this mean that I would have to remove some freon if running only a 15' lineset? Or am I good to go as long as I dont go with the 35'-100' linest?

Pad or Wall Bracket - to mount outdoor unit
Control Wire - to provide power to inside unit from outdoor unit.

Should I go with their offered electrical whip and electrical disconnect? Would I run the appropriate size wire near the perimeter of my basement ceiling (install a box) and run the electrical whip to the outside disconnect and AC unit? Or is the electrical whip just to run from the disconnect to AC unit - me providing the wire from panel to disconnect?

What about drain hose for condensate? Does the indoor and/or outdoor unit need these?

I'll need to run wire from my panel on the opposite side of the basement over to the other side and out the house rim joist.

Anything else I should know/need?

I know I'll be needing a vacuum pump and a gauge set for the install. This info was on here somewhere but if anyone can recommend brand/site to purchase from (harbor freight?) it'd be greatly appreciated.


Thanks

 

[Guest 18340]

Hey all,

So I'm going to bite the bullet and get a 36k Mr Slim Split so that I can build out a proper 8k room.

I've got a few questions. I've been looking at the units from goductless ..they have 2 listed however

Mr. Slim 34,600 BTU 15.1 SEER Single Zone Ductless Mini Split

Mr. Slim 36,000 BTU 14.5 SEER Heat Pump Single Zone Ductless Mini Split

Which one do I want? The 34k is cooling only. The 36k has a heat pump. Do I want the heat pump model since I'll be running it in a climate that experiences winters 20-30F somtimes down to single digits?
Get the heat pump model. I live in a similar climate as you and occasionally switch to heat mode in the winter when lights are out. Better safe than sorry...
Also..
The unit only seems to include the indoor, outdoor, remote, and mounting plates for the indoor unit. So to be clear I'll needing the following accessories.

Lineset - Indoor unit will be close to outdoor unit so 15' should be adequate however I've heard the units are pre-charged for 25' (i think). Does this mean that I would have to remove some freon if running only a 15' lineset? Or am I good to go as long as I dont go with the 35'-100' linest?
Get the 25' line set. Otherwise you will have to remove some "freon" (r410a), and thats not as simple as letting some out to the atmosphere. You can leave any excess line set coiled up. Mine runs up the outside wall, through the attic, and down to the indoor unit. The excess is coiled up in the attic.
Pad or Wall Bracket - to mount outdoor unit

It easier to put it on a pad on the ground, but it's really a matter of preference and whether you have the space on the ground...
Control Wire - to provide power to inside unit from outdoor unit.

Yes, you'll need a control wire. You can buy it at ANY lowes, HD, etc. The install manual tells you what size wire is need. It's something like 14awg...

Should I go with their offered electrical whip and electrical disconnect? Would I run the appropriate size wire near the perimeter of my basement ceiling (install a box) and run the electrical whip to the outside disconnect and AC unit? Or is the electrical whip just to run from the disconnect to AC unit - me providing the wire from panel to disconnect?

It goes like this, 12gauge "power" wire from your breaker box, to the outside disconnect, whip from disconnect to outside unit. Control wire goes from outside to indoor unit. The outdoor unit powers the indoor unit.
What about drain hose for condensate? Does the indoor and/or outdoor unit need these?
The indoor unit has the drain hose. You can plumb it outside, the same way a central unit has a drip tube coming from the air handler, or you can simple put a bucket or 55 gal rez in the room under the head unit to catch the water. But regardless, it's the indoor unit that has the drain. Buy the drain tubing from the same place your buying the unit.

I'll need to run wire from my panel on the opposite side of the basement over to the other side and out the house rim joist.

Anything else I should know/need?

I know I'll be needing a vacuum pump and a gauge set for the install. This info was on here somewhere but if anyone can recommend brand/site to purchase from (harbor freight?) it'd be greatly appreciated.


Thanks

My answers are in bold.

 

[FlowerFarmer]

Awesome.. thanks man.

Exactly the clarification I needed.

I've got a sante fe classic on the way and going to order the 3 ton split w/ heat pump.. Should be fun.

 

[OneTokeOver]

Perfect timing.

evlme2, do you set the one temp for lights on and off and then the unit switches from cooling to heating as required?

Or is there a programmable thermostat?

I am buying a 2 zone for 2 rooms and would love to not have to install heaters.

 

[Guest 18340]

In the winter time when I know the temps outside are gonna drop when my lights are off, yes I'll set it so the heat automatically comes on. It's called "auto changeover". For example, I'll set the temps to 79 in auto changeover mode. The unit will automatically cycle between heat and cool to keep the temps within a +/- 5 degrees of 79. (Not sure if it's 5 or 4 degrees but you get the picture)
You guys are gonna love those Mitsu's!

 

[OneTokeOver]

Thanks very much, bro.

 

[Guest 18340]

FlowerFarmer, as far as gauges and pumps go ebay is your best bet for decent prices.
I personally use a JB pump but Robinair (SP) is decent for our purpose. The higher the cfm the better. And make sure it's a dual stage pump cause you need to pull a pretty deep vacuum. Buy vacuum pump oil as well.
Make sure the gauges you buy are specifically for R410a.
And lastly, if you can afford it, I would get a micron gauge. Preferably a digital one. The factory calls for a vacuum of 500microns or less and the only way to read that is with a micron gauge. The manifold gauge set only shows -30hg.
You can get away with just using the manifold gauge set and vacuuming for a few hours but the only way to tell if you've reached 500 microns or less is with a micron gauge.
Not 100% necessary, especially if you've verified that theirs no leaks in the system, but it's cheap insurance imho.

 

[black_thumb]

you will need a drain line for the indoor unit it only comes with 3 feet of drain line. dont take any freon out.
and dont over tighten the smaller 3/8 line or it will leak.
you need to cheek for oil/freon leaks at every fitting after you install it and run it for an hour or 2. you can use soapy water and spray on the fittings and see if there are any small bubbles.

you need a good 2 stage pump and pull down to -30 vac

 

[OneTokeOver]

Hmmm, was gonna get my neighbor (hvac guy) to hook mine up but am now wondering if said vacuum pump would also work well for vacuum purging BHO?

 

[Guest 18340]

Hmmm, was gonna get my neighbor (hvac guy) to hook mine up but am now wondering if said vacuum pump would also work well for vacuum purging BHO?

Yes it does. Ask me how I know...

 

[OneTokeOver]

Nice!!!!

I sense more ? coming your way soon.

 

[FlowerFarmer]

FlowerFarmer, as far as gauges and pumps go ebay is your best bet for decent prices.
I personally use a JB pump but Robinair (SP) is decent for our purpose. The higher the cfm the better. And make sure it's a dual stage pump cause you need to pull a pretty deep vacuum. Buy vacuum pump oil as well.
Make sure the gauges you buy are specifically for R410a.
And lastly, if you can afford it, I would get a micron gauge. Preferably a digital one. The factory calls for a vacuum of 500microns or less and the only way to read that is with a micron gauge. The manifold gauge set only shows -30hg.
You can get away with just using the manifold gauge set and vacuuming for a few hours but the only way to tell if you've reached 500 microns or less is with a micron gauge.
Not 100% necessary, especially if you've verified that theirs no leaks in the system, but it's cheap insurance imho.

I see - Thanks.

How much CFM are we talking?

I've looked at some JB pumps and they are 2-stage from 4cfm - 10cfm ranging from $260-700.

Harborfreight (US General brand pump) has a 3cfm 2 stage for $160. Too cheap to risk it?

I also found a 4cfm JB for $260
JB DV-4E 4 CFM Eliminator Vacuum Pump, 115V/60Hz Motor, with US Plug

They have a 6cfm JB for $300
Do I need to spend the $500 on a 7cfm+?

 

[Guest 18340]

Imho 3cfm/2 stage will get the job done. It may take a little longer to reach 500 micron with a 3 cfm pump over a 7 cfm but either will get the job done.

 

[FlowerFarmer]

Few more questions.

I'm trying to figure where I'd like to put this. I want it in the back corner of my house near my house central air unit, but there are a few issues.

My home is built on a hill so the side of it is exposed block foundation/basement. The current ac is mounted here to the home's rimjoist where foundation meets the home. I ideally I'd want the split next to it, but there is a glass block window there.

Can I mount the split brackets to the block foundation below the glass block window..meaning the back of the split would block the glass block window (not really block it, but in front of it)...and would also be staggered down in relation to the home ac as more of the foundation is exposed and can be hung lower. That make any sense to you?

If I cannot have it lower as more foundation is exposed can I mount to rim joist next to current AC.. the brackets would likely ride down each side of the glass block window (hopefully not over it), but the block window would be directly below the suspended split.

Alternatively I have a nice spot where I could put a pad around the corner from the house AC on the back of the house. Unfortunately is there a hose spigot centered right there. Can I put the split in front of it? It wouldnt be used as I have other spigots, but I dont want anyone for whatever reason to walk around my house and determine that it isnt code/no permit etc.. and cause issue. I live in a rural area with land, but do tax people etc inspect this type of stuff?

 

[Guest 18340]

Few more questions.

I'm trying to figure where I'd like to put this. I want it in the back corner of my house near my house central air unit, but there are a few issues.

My home is built on a hill so the side of it is exposed block foundation/basement. The current ac is mounted here to the home's rimjoist where foundation meets the home. I ideally I'd want the split next to it, but there is a glass block window there.

Can I mount the split brackets to the block foundation below the glass block window..meaning the back of the split would block the glass block window (not really block it, but in front of it)...and would also be staggered down in relation to the home ac as more of the foundation is exposed and can be hung lower. That make any sense to you?
Sorta/kinda makes sense...
It sounds like the unit would be sitting openly. If you're ok with that then it's an option. That is if I'm understanding you...

If I cannot have it lower as more foundation is exposed can I mount to rim joist next to current AC.. the brackets would likely ride down each side of the glass block window (hopefully not over it), but the block window would be directly below the suspended split.
I think your only problem might be that your glass block window is wider than the mini split's mounting tabs. The tabs are 19 and 11/16 inches apart. If the window is wider than that then it won't fit.


Alternatively I have a nice spot where I could put a pad around the corner from the house AC on the back of the house. Unfortunately is there a hose spigot centered right there. Can I put the split in front of it? It wouldnt be used as I have other spigots, but I dont want anyone for whatever reason to walk around my house and determine that it isnt code/no permit etc.. and cause issue. I live in a rural area with land, but do tax people etc inspect this type of stuff?

I don't think the tax man would care about that. He'd have no way of knowing if it's an old spigot that is disconnected. Just wrench on a cap and take the handle off the spigot and you'll be golden.

 

[FlowerFarmer]

Good idea..

That'd be the easiest thing to do, but I'm not sure I want it there. My deck area is on that side. I know these units are really quiet but its more the concern of friends noticing it. If I ever have my hvac buddy here to cook out or something he'll surely notice the addition and it might raise eyebrows asking why I needed more cooling somewhere and how I managed the install, etc myself. Nosey..since he is in the trade. Might seem paranoid to some, but its just the little things. I don't need to spark any light bulbs any more then my lifestyle already may have.

Few more questions if you dont mind. I'm going to keep throwing them at you as I actually receive this thing.

Do you have experience with the line-sets from goductless. I've heard many dont trust the pre-flared linsets. If I ensure they are free of burrs and don't overtightened are they good to go?

Doing some research I also heard varying things on the coiling of the extra line-set. Many say don't do it due to reduced efficiency?? Also heard this:

"If you have extra line set length, do not "coil" (as in loops)the tubing. You can run it in a serpentine pattern. Look at the coil on the back of a refrigerator"

If I am mounting directly on the wall where the outdoor unit is location I'm going to have a lot of extra line-set. 15' is too much.. let alone having to go 25' to avoid having to evacuate/cut/flair, etc.

I'm going to be at the max in terms of cooling capacity as I'll have 8k uncooled with propane co2 burner and sante fe dehumidifier.

Room is 11x16. Air handler best placed in the middle of the 16' wall? If I go that route it'd chew up a little bit of lineset so maybe not as much coiling would be needed.

Edit - Heard another issue sometimes is that the units lose a bit of their pre-charge from the factory...depending on when the unit was manufactured and getting banged around in shipping. Common with mr slims? Or are these problems people are having with budget units?


Thanks for the replies.

 

[Guest 18340]

Good idea..

That'd be the easiest thing to do, but I'm not sure I want it there. My deck area is on that side. I know these units are really quiet but its more the concern of friends noticing it. If I ever have my hvac buddy here to cook out or something he'll surely notice the addition and it might raise eyebrows asking why I needed more cooling somewhere and how I managed the install, etc myself. Nosey..since he is in the trade. Might seem paranoid to some, but its just the little things. I don't need to spark any light bulbs any more then my lifestyle already may have.
Just so you know, you can put the unit under a deck as long as you have the height for it...

Few more questions if you dont mind. I'm going to keep throwing them at you as I actually receive this thing.

Do you have experience with the line-sets from goductless. I've heard many dont trust the pre-flared linsets. If I ensure they are free of burrs and don't overtightened are they good to go?
I've installed three units bought from goductless, with line sets. Every single one leaked. I had to cut of the ends and reflare.

Doing some research I also heard varying things on the coiling of the extra line-set. Many say don't do it due to reduced efficiency?? Also heard this:

"If you have extra line set length, do not "coil" (as in loops)the tubing. You can run it in a serpentine pattern. Look at the coil on the back of a refrigerator"
The coil on the back of a fridge is not the same thing as a line set...I've had my Mitsu running flawlessly for almost 2 years now with the line set coiled so i can tell you from experience.
If I am mounting directly on the wall where the outdoor unit is location I'm going to have a lot of extra line-set. 15' is too much.. let alone having to go 25' to avoid having to evacuate/cut/flair, etc.

I'm going to be at the max in terms of cooling capacity as I'll have 8k uncooled with propane co2 burner and sante fe dehumidifier.

Room is 11x16. Air handler best placed in the middle of the 16' wall? If I go that route it'd chew up a little bit of lineset so maybe not as much coiling would be needed.
Your alternative is to remove freon. But its not as easy as cracking the service vale and letting some out. The instruction manual will tell you how much r410 to add/subtract per foot of line set. It is MUCH easier to just coil up any extra length.
Here's a vid on an LG install done by a tech...
http://www.youtube.com/watch?v=qI5IrR8PceU
Edit - Heard another issue sometimes is that the units lose a bit of their pre-charge from the factory...depending on when the unit was manufactured and getting banged around in shipping. Common with mr slims? Or are these problems people are having with budget units?
NEVER had a Mitsu come under charged or leaking. With budget units though, you get what you pay for...

Thanks for the replies.

No prob...

 

[Vegan]

real good read on mini split details thanx guys. also I just installed a Fedders unit that did not have R410 fittings. I had to use a adapter to vacume the lines

 

[Guest 18340]

real good read on mini split details thanx guys. also I just installed a Fedders unit that did not have R410 fittings. I had to use a adapter to vacume the lines

Ah yes, it's the little details that'll get you every time. I do know that the Mitsu's do not need that adapter. I bought one thinking it was need, luckily... I say that cause I recently installed an LG and it required an adapter...

 

[FlowerFarmer]

Evlme2, thanks that video was one of the better ones on youtube.

So you can go ahead and try using their flaired ended lineset and you'll know if its leaking based on it not holding vacuum down? This will become apparent before releasing any r410a into the system?

At that point you can disconnect and re-flair the ends? How challenging is this? Do you just need a flaring tool and a pipe cutter? Or would I be better off taking the lineset to a pro to have it cut and re-flared?

I went ahead and ordered the split +parts along with the lineset from another website. (goductless was backordered on 3/8 & 5/8 lineset). Everything is on the way. Going to pick up the 2 stage vacuum pump from harbor freight. Its got pretty good reviews on their website.

In regards to the r410a manifold gauges. Do I need ones for r410a as pictured below AND a digital micron gauge.. or would spending extra on the digital micron gauge negate the need for the unit pictured below.

Much appreciated..