Welcome to the The Garage Journal Board forums.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   The Garage Journal Board > The Garage > Heating and A/C

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Search this Thread Display Modes
Old 05-03-2012, 06:03 PM   #1
rvr6000
Senior Member
 
rvr6000's Avatar
 
Join Date: Oct 2010
Location: St. Paul, MN
Posts: 1,047
Default Mini-split AC questions

Long story short, the misses and I live in a 1 1/2 story home. Our bedroom encompasses the whole upper level (about 400sq ft). We're tired of the old window unit we put in every year (drug it in from the shed again today) to help keep it cool up there and have been talking about getting a mini-split ac system.

I would consider myself fairly mechanically inclined - Is this something I could tackle myself? I'm lucky in that where the indoor unit would be located is directly above where the compressor would be so no crazy line-set issues that I can foresee.

Speaking of the line-set, since it's gonna be visible from the outside, do these things just look like hell or is there a way to conceal them from view?

Power - If I understand what I have seen and read, the indoor unit gets it's power from the outside compressor? No need to run a special circuit or plug the inside unit into a wall outlet? Just have to run a circuit (240volt I assume) to the compressor.

Which model - always up for debate but what model/manufacturer do you guys recommend?

Thanks in advance for all your help.
rvr6000 is offline   Reply With Quote
Old 05-03-2012, 06:12 PM   #2
green.bubbly
Senior Member
 
green.bubbly's Avatar
 
Join Date: Dec 2008
Location: Lafayette, LA
Posts: 1,634
Default Re: Mini-split AC questions

Installation is pretty straight forwards if you have any basic construction experience. Most units come with flared linesets so there is no need to braze or solder. I would suggest calling in a professional AC person to vacuum the lines and set the charges correctly.

There are lineset covers that conceal the linesets with a plastic channel. Not the best looking thing but not the worst either. Depending on the size of the unit, you would typically run the 120 or 240 power to the outside unit which then powers the inside unit.

I installed a cheap Klimaire last year in my garage and it seems to be doing fine but one year is not a good test. Depending on how much you will be running it, there are the cheapo inefficient models and then there are the more expensive high efficiency units.


Do a search, there are several threads on this topic with lots of great info.

Here is a good thread...

http://garagejournal.com/forum/showt...ighlight=split
__________________
.
.
.
.
.

_______________________________________

My garage and steel home build thread...
http://garagejournal.com/forum/showthread.php?t=91518

Last edited by green.bubbly; 05-03-2012 at 06:14 PM.
green.bubbly is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 05-03-2012, 07:04 PM   #3
rvr6000
Senior Member
 
rvr6000's Avatar
 
Join Date: Oct 2010
Location: St. Paul, MN
Posts: 1,047
Default Re: Mini-split AC questions

Thanks, Green. I was wondering about those line-sets if they needed brazing or not. Have been reading that post my mpire too. Good info.
rvr6000 is offline   Reply With Quote
Old 05-03-2012, 09:47 PM   #4
ghnl
Senior Member
 
ghnl's Avatar
 
Join Date: Mar 2009
Location: Mebane, NC
Posts: 982
Default Re: Mini-split AC questions

The installation is not difficult. I agree that paying an HVAC tech to vacuum the lines (and adding refrigerant if needed) is a Good Idea.

They make line set covers (expensive for what they are however). I used a length of downspout (rain gutter stuff) and modified a clothes dryer vent for the top.
Attached Images
File Type: jpg lineset cover 02.jpg (73.5 KB, 118 views)
File Type: jpg lineset cover 01.jpg (29.6 KB, 95 views)
__________________
Eric
Mebane, NC
'61 MGA, '84 Alfa Romeo Spider
'81 Alfa Romeo GTV-6, '91 Honda ST1100,
'99 F250 diesel, '06 Toyota Solara
My home page
ghnl is offline   Reply With Quote
Old 05-03-2012, 10:04 PM   #5
JakeKohl
Senior Member
 
JakeKohl's Avatar
 
Join Date: Feb 2012
Location: Greenville, SC
Posts: 1,343
Default Re: Mini-split AC questions

If you are skilled with electrical and mechanical, getting the units in place is not very difficult. The tricky bits come in to play when you need to shorten the linesets and evacuate / charge the system. Unless you have some attic space to run the extra copper lineset, you will probably need to trim to fit. I've also heard that it's not wise to trust the factory flare on the purchased line sets. R410A that all of the split units are charged with now is very sensitive to a proper charge and it needs to be right to get the efficiencies out of the system. Hiring someone to come in and make the final connections, evacuate the system, and adjust the charge shouldn't be very costly if you've done everything else.

I've got two 18k btu split heat pump units that I'm in the process of installing and I've learned a bit. I've got an enough HVAC and engineering background to be dangerous but I have the manifold set and vacuum equipment to complete installation so I feel that this is within my reach. A couple of key items to consider:
  • The flare on 410A systems is a 45 degree flare and requires a specific flare kit - not the 60 degree flare commonly used elsewhere
  • the charge of the unit should idealy be adjusted to include the length of the lineset. Most systems are precharged for 25 feet. If longer, you need to add refrigerant. If shorter, you need to remove refrigerant.
  • Indoor unit is typically powered by the outdoor unit through an 18 guage 4 or 5 conductor cable so the only romex you need to pull is to the outdoor unit.
  • ghnl is right, they do make covers including nice 90 degree through-wall fittings - but they are stupidly expensive. Short of using gutter downspout or running the linesets in the interior wall (like I did since I had full interior access at the time), there aren't many other options.
  • dryer vents and a little spray foam make great wall penetration points for the lineset!







__________________
Jake Kohl
Greenville, SC

My Garage Journal Build Thread

"People complain about it being too expensive. People complain about it being too small. Nobody complains about it being too big."

Last edited by JakeKohl; 05-03-2012 at 10:14 PM.
JakeKohl is offline   Reply With Quote
Old 05-03-2012, 10:28 PM   #6
rvr6000
Senior Member
 
rvr6000's Avatar
 
Join Date: Oct 2010
Location: St. Paul, MN
Posts: 1,047
Default Re: Mini-split AC questions

ghnl: If you didn't tell me what those covers really were I never would've guessed. They look factory made.

Jake: I wouldn't have any problem setting the compressor and doing the electrical. The more I think about it I could just call the guy who installed my furnace last year and have him make the final connections. He's easy going, does nice work and I'm sure wouldn't mind doing something like that for cash. By the way, your install looks very nice.
rvr6000 is offline   Reply With Quote
Old 05-04-2012, 06:53 AM   #7
JakeKohl
Senior Member
 
JakeKohl's Avatar
 
Join Date: Feb 2012
Location: Greenville, SC
Posts: 1,343
Default Re: Mini-split AC questions

rvr6000, thanks for the compliment.

ghnl, I just realized you DID use gutter downspout - had to look closely! That looks great.
__________________
Jake Kohl
Greenville, SC

My Garage Journal Build Thread

"People complain about it being too expensive. People complain about it being too small. Nobody complains about it being too big."
JakeKohl is offline   Reply With Quote
Old 05-04-2012, 07:43 AM   #8
bigdav160
Senior Member
 
bigdav160's Avatar
 
Join Date: Apr 2007
Location: Deep in the heart of Texas
Posts: 744
Default Re: Mini-split AC questions

I installed a Sanyo Inverter mini split in our extra large master bedroom. (900 sq/ft)

The hardest part with my install was running the romex. Like Jake I built brackets to hold the condenser unit. Even though I have a quality flare tool, my flares leaked. I went back and soldered the lines and recharged.

The unit works great and I no longer have to cool 3000 sq/ft to make the bedroom comfortable.
__________________
My Classics:
1972 K20 Suburban
1963 Ford SWB Uni
1965 Dodge Town Wagon
1967 Vette Roadster 4-Speed no PB
1972 Vette Roadster 4-Speed no PS
1973 Chevy Z-28
1950 Ford Club Coupe
My Toys:
2002 BMW R1100S
1996 Ski Centurion Elite V-Drive wTower
1998 El Pescador 24

Our Transportation:
Mine- 2001 Dodge Ram Laramie/SLT 4x4 QC Long Bed. CTD HO/6 Speed. White over Silver
Hers- 2003 Dodge Ram 2500 Laramie 4x4 Quad-Cab Sport. CTD HO/48RE Bright Silver Metallic
bigdav160 is offline   Reply With Quote
Old 05-04-2012, 10:04 AM   #9
Highbeam
Senior Member
 
Join Date: Feb 2011
Location: South Puget Sound
Posts: 1,909
Default Re: Mini-split AC questions

With such nice exterior unit installations could you folks show us the interior side? If the inside units could look good, then I think that these things would become more mainstream. Don't forget about condensate, you need to drain that from the indoor units too.
Highbeam is offline   Reply With Quote
Old 05-04-2012, 10:31 AM   #10
JakeKohl
Senior Member
 
JakeKohl's Avatar
 
Join Date: Feb 2012
Location: Greenville, SC
Posts: 1,343
Default Re: Mini-split AC questions

Quote:
Originally Posted by Highbeam View Post
With such nice exterior unit installations could you folks show us the interior side? If the inside units could look good, then I think that these things would become more mainstream. Don't forget about condensate, you need to drain that from the indoor units too.
I haven't gotten that far yet - hoping to start installing the interior units next weekend...which, in my case, is a little tricky. Because my linesets (and drainlines) are run inside the wall, I need to (ideally) make all of these connections before the insulation and dry wall are installed. However, the interior units mount on the surface of the drywall. So my choice is to do insulation and drywall and then cut out access panels to get to the connection points, or hang just enough insulation and drywall to mount the unit but leaving the connection points (later to be enclosed in the wall) exposed while I finalize installation. I'm going with the latter plan and if I have any issues, I can cut in the access panels later (hopefully the inspector won't have an issue with this method).


In the case of my downstairs/garage unit, it mounts to a wall that has attic access behind it from the original building structure...so that part is much easier and the connections can just be made in the attic.
__________________
Jake Kohl
Greenville, SC

My Garage Journal Build Thread

"People complain about it being too expensive. People complain about it being too small. Nobody complains about it being too big."
JakeKohl is offline   Reply With Quote
Old 05-04-2012, 08:14 PM   #11
ghnl
Senior Member
 
ghnl's Avatar
 
Join Date: Mar 2009
Location: Mebane, NC
Posts: 982
Default Re: Mini-split AC questions

Quote:
Originally Posted by Highbeam View Post
...could you folks show us the interior side?
Very unobtrusive and quiet. No louder than a small fan.
Attached Images
File Type: jpg minsplit 02.jpg (50.2 KB, 112 views)
__________________
Eric
Mebane, NC
'61 MGA, '84 Alfa Romeo Spider
'81 Alfa Romeo GTV-6, '91 Honda ST1100,
'99 F250 diesel, '06 Toyota Solara
My home page
ghnl is offline   Reply With Quote
Old 05-04-2012, 08:20 PM   #12
green.bubbly
Senior Member
 
green.bubbly's Avatar
 
Join Date: Dec 2008
Location: Lafayette, LA
Posts: 1,634
Default Re: Mini-split AC questions

Quote:
Originally Posted by JakeKohl View Post
I haven't gotten that far yet - hoping to start installing the interior units next weekend...which, in my case, is a little tricky. Because my linesets (and drainlines) are run inside the wall, I need to (ideally) make all of these connections before the insulation and dry wall are installed. However, the interior units mount on the surface of the drywall. So my choice is to do insulation and drywall and then cut out access panels to get to the connection points, or hang just enough insulation and drywall to mount the unit but leaving the connection points (later to be enclosed in the wall) exposed while I finalize installation. I'm going with the latter plan and if I have any issues, I can cut in the access panels later (hopefully the inspector won't have an issue with this method).


In the case of my downstairs/garage unit, it mounts to a wall that has attic access behind it from the original building structure...so that part is much easier and the connections can just be made in the attic.

Good looking install. I see you have a couple more units in your garage.

I did the same thing you want to do with running the lineset and grain line in the wall when I did my garage. I was a pain in the but since I was putting OSB sheets on my wall. I cut out an access panel as well below my unit so I could connect the lineset and drain.
__________________
.
.
.
.
.

_______________________________________

My garage and steel home build thread...
http://garagejournal.com/forum/showthread.php?t=91518
green.bubbly is offline   Reply With Quote
Old 05-04-2012, 08:59 PM   #13
JakeKohl
Senior Member
 
JakeKohl's Avatar
 
Join Date: Feb 2012
Location: Greenville, SC
Posts: 1,343
Default Re: Mini-split AC questions

Quote:
Originally Posted by green.bubbly View Post
Good looking install. I see you have a couple more units in your garage.

I did the same thing you want to do with running the lineset and grain line in the wall when I did my garage. I was a pain in the but since I was putting OSB sheets on my wall. I cut out an access panel as well below my unit so I could connect the lineset and drain.
You caught me... I started with 12k btu units but later got nervous that I didn't include enough safety factor in my load calcs. I upgraded to 18k btu heat pumps instead. The one ton units are sold to a new home and headed there this weekend.
__________________
Jake Kohl
Greenville, SC

My Garage Journal Build Thread

"People complain about it being too expensive. People complain about it being too small. Nobody complains about it being too big."
JakeKohl is offline   Reply With Quote
Old 05-08-2012, 04:15 PM   #14
RKA
Senior Member
 
Join Date: Jun 2010
Location: NJ
Posts: 901
Default Re: Mini-split AC questions

Good looking install Jake! My suggestion is to sheetrock where you'll be mounting the indoor unit and hang it, make the connections and pressure test with nitrogen. Once you're certain everything is good n tight, close up the walls
RKA is offline   Reply With Quote
Old 05-09-2012, 05:17 PM   #15
flybefree
Senior Member
 
flybefree's Avatar
 
Join Date: May 2008
Location: Ohio/Kentucky
Posts: 1,112
Default Re: Mini-split AC questions

I bought my mitu unit online and payed local guy $500 to install, came in way under the full quotes I had and I still have a valid warranty.

Shaun
__________________
Hyperbole Alert! Life with my dream garage, girl, kids, and car.http://www.garagejournal.com/forum/s...d.php?t=110364

All Men are Created Equal...the difference is what they do after that.
flybefree is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 12:29 AM.