Mini split planning

[katit]

I'm in a "design" phase of finishing my garage. Here is my questions. If someone can answer them - I will appreciate it.. Here in STL we have couple cold weeks but nothing too bad. Garage is 22x22 inside, 8ft ceiling with one bay raised to 10ft

1. According to online calculators in well insulated garage 18000 btu will be plenty enough, 12500 should be OK. Should I go with 18000 or stop at 12500?

2. According to mini-split instructions heat pump will work well down to 20 degrees. Inside? Outside? We have maybe 1-2 weeks of very cold. According to online data - coldest is January at low 22 degrees. I probably going to skip on electric heat option. What do you think?

3. Installation. I have masonry construction. Which means if I put outside unit on a slab - I will have to make 3 inch hole in a brick wall. Install box, etc. I have rear entry garage so the only place to put unit will be on a right side of the house if you look from the street. Aestatically wrong IMO. Wife may not like it. High traffic area. Can I place it on a roof? If I place on a roof - it won't be visible, I won't have to drill brick. Is it acceptable to mount unit on a roof? Where is box going to be? How is wire going to lay on a roof?

4. I will install inside unit on a wall in raised portion of ceiling. So, it will be like 9ft high and I will be able to get drain through the siding, not brick. Is it OK position for inside unit?

Thanks in advance!

 

[sneezer41]

Place the outside unit where it is convenient to the inside unit. brick is soft and I would buck up and drill the hole where you want it, ugly lasts forever, your arm will only hurt for a day.

9 feet is probably perfect, no point in really high, pain in the **** if too low.

20 degrees outside it will work, but not be really efficient.

 

[katit]

ugly lasts forever,

Thats what it will be if I drill brick and install it on a ground next to garage.
Since inside unit is at 9ft - shortest run will be up to the roof. No conduits, no holes in a brick, invisible from a street. But is it legal?

Or maybe I can mount it on a side above brick wall? Then it will kind of blend with white siding and hose run will be very short.

If I DO set it next to garage on a slab then I will have:
a. Outlet (hole) on a bottom and conduit on INSIDE wall to carry hoses and wires from inside unit to the bottom.
OR
b. Otlet (hole) on a top and conduit on OUTSIDE brick wall going down to the condensor.

 

[TheShrine]

I'm in a "design" phase of finishing my garage. Here is my questions. If someone can answer them - I will appreciate it.. Here in STL we have couple cold weeks but nothing too bad. Garage is 22x22 inside, 8ft ceiling with one bay raised to 10ft

1. According to online calculators in well insulated garage 18000 btu will be plenty enough, 12500 should be OK. Should I go with 18000 or stop at 12500?
I have a 12500 in my garage that is 27 X30. It is well insulated w/ double pane windows. I am in central Texas with what sounds like similar weather as you. My downstairs 12500 unit is an inverter w/o a heat strip and it warms fine as well. My upstairs unit is an 18000 w/inverter and really should be 12500 or less.

2. According to mini-split instructions heat pump will work well down to 20 degrees. Inside? Outside? We have maybe 1-2 weeks of very cold. According to online data - coldest is January at low 22 degrees. I probably going to skip on electric heat option. What do you think? My inverter unit warms just fine...of course my garage is well insulated.

3. Installation. I have masonry construction. Which means if I put outside unit on a slab - I will have to make 3 inch hole in a brick wall. Install box, etc. I have rear entry garage so the only place to put unit will be on a right side of the house if you look from the street. Aestatically wrong IMO. Wife may not like it. High traffic area. Can I place it on a roof? If I place on a roof - it won't be visible, I won't have to drill brick. Is it acceptable to mount unit on a roof? Where is box going to be? How is wire going to lay on a roof? Roof mount is fine. I mounted mine on the wall. Beyond aesthetics you should be concerned with the distance of the inside from the outside units. Each manufacturer has limitations, usually about 25'. The distance can be increased with decrease eficency. Each manufacturer has different rules.

4. I will install inside unit on a wall in raised portion of ceiling. So, it will be like 9ft high and I will be able to get drain through the siding, not brick. Is it OK position for inside unit? I know of no split system manufacturer that does not recommend direct through the wall installation. Most recommend the inside unit be installed on an outside wall. You'll notice that the install kit will come with the items needed to install on an outside wall. I installed mine, both upstairs and downstairs on inside walls and ran all of the copper, drain and communication lines though the walls. I was challenging but it can be done. PRE-PLAN THE DISTANCE AND THE ROUTE!

Thanks in advance!

I hope this helps. I have other pics if you have other questions....but pre-planning is the answer!

 

[ghnl]

As stated, a 3" hole through a brick wall should not be too difficult. Place the outside unit where it can get 220V supplied, a free flow of air, etc. The outside units are not too large or ugly so place it where it needs to be. Cover the linesets and it'll look fine. I used some PVC downspout (as in rain gutter) and a through the wall fitting for a dryer vent. They make lineset covers specifically for the job but they are fairly expensive (and I'm cheap...)

FWIW, I used an 18,000 BTU unit for our 25'x42'x12' garage & a second 18,000 BTU unit for the room above (wood framed with average insulation). They have no problems keeping the garage or bonus room warm with outside temps in the high 20's/30's.

 

[Rolling_Thunder]

Im in a 23x23 inside and have a 18k unit with a heating element in my garage.
The walls are R13 with 15/32 plywood for walls. The ceiling is open right now going to close it in after Xmas. I went with a unit from Ramsond 18k with a Heat strip for those really cold days. So far it works great both summer & Winter. Ive used it on days in the low 30's and even with no ceiling insulation it warmed the area up real nice!! Here is the Unit I bought! I installed it myself in about 4 hours wiring and all.

http://www.ramsond.com/proddetail.php?prod=R55GW&cat=Ductless Mini Split AC Systems

 

[katit]

Looks like the best way for me will be to mount units right next to each other. Hoses can be as short as 5 feet. From what I understand - they come ready to install, so I will have to spool and hide extra hose somewhere. Or can I cut it to size somehow?

Thanks for all advices so far. It looks like 12500 without heat strip will be all I need.

 

[ghnl]

I bought the same Ramsond unit. They come with 15' linesets. I would cut the copper tubing to length & make a new flare on the cut end (remembering to slide the flare nut onto the tube first...). There is also 2 or 3 14 ga wires (to run the inside unit's blower motor) and some small ga wires (for the T-stat control I think).

 

[jm1fd]

With conventional split systems, you have to do things a bit differently with the refrigerant lines if the condenser is going to be higher than the evaporator to ensure proper oil return. I'm not sure if this applies to mini-splits or not, but I would suspect it does.

 

[ghnl]

According to Ramsond's installation instructions, either unit can be higher. It doesn't mention that anything special needs to be done if the outdoor unit is higher.

 

[katit]

Another question about electrics. I'm planning my electrics right now.
Do I need 220V? Is 20A enough? How is those units wired, is it permanent or they use wall outlet? I can't see on a pictures where those units plugged in?

 

[slickracer]

My Mitsubishi 12,000 BTU unit runs on 220V 15A circuit. Produced nice heat down to 12 degrees outside temp.

 

[ghnl]

The Ramsond unit I bought is 'hard wired' to an electrical box on the outside wall. I had the electrician run the 220V circuit to that, then it was a simple matter to connect the wires from the heat pump and turn on the circuit breaker.

 

[katit]

Thanks Eric! That's what I was looking for. So, just install box outside somewhere around and that should be good enough.

 

[ghnl]

Yep. I ran the wires inside some flexible electrical conduit between the electrical box & the heat pumps. You can buy it by the foot at Lowes. Add some fittings at each end for a strong, protected install.

 

[Ironcrow]

That Ramsond looks like a pretty good gig. Do they have an on-line calculator to size the unit? Or is there another good site for this?

 

[Jazz]

I am also considering mini splits for my new garage and another for an entertaining area separated from the garage workspace. The garage willl get one unit and the living space (which is two separage rooms, one upstairs above the garage and one behind the garage) will either get a dual zone unit or two separate units. I was wondering if there's any advantage to the two zone units over the one zone for installation or efficiency.

 

[ghnl]

My research indicated that if the two units are likely to be operated separately then get two separate units. If you are conditioning a large area or different spaces of the same living area (say, living room & bedroom) then the dual unit is best.

 

[TX-WJ]

http://www.ramsond.com/proddetail.php?prod=R55GW&cat=Ductless Mini Split AC Systems

Wow, that price is pretty competitive for an 18K BTU heat pump unit when compared to the Mitsubishi ones (the "gold standard" I guess). Are there any reviews on these ramsond units? anyone?

 

[jayrush13]

I didn't see any one answer your question on putting it on the roof I install these all the time for the company i work for we put them on roofs of office buildings and houses to get them out of the way shouldn't be any problem

 

[hblock72]

Anyone know why the to dual units cost so much more? You can buy 2 seperate units cheaper than you can buy one dual unit. Just didn't make any sense to me, or am I looking at something wrong?

 

[katit]

Thank you everyone for all of the advice so far. I planned way before but just yesterday I received shipment and almost ready to do install. I got 18000 btu Ramsond with heat strip as discussed above.

Challenges/questions:
1. Position of inside unit. If I mount it where I wanted it above window then I will only have 3" of space above unit. Instruction calls for 6". Is it really crytical? Is it air intake above?

2. I mounted electric box INSIDE in attic with 12/2 romex for 220v. Now I will need to connect it to outside unit that will be mounted on a wall next to that box. Should I place another box outside and run romex into that outside box and then connect flex pipe to route electricity to condensor?

3. Pipes. If I do everything where I want it to be then my lines will be about 6-7'. I got 15' lineset. I have no flaring equipment. Should I make my best and try to shorten lines or just coil them in attic will work fine? I have unused space in attic box and cosmetically it will be just fine..

4. For those who mounted unit on outside framed wall. It's pretty heavy. Does it feel sturdy? What about vibrations? That spot is the best for me to mount but I wonder about vibrations.

5. Do I need disconnect for this unit? Or is there code requirement for that? Maybe instead of box I mentioned in #2 I should get some kind of disconnect box that will server purpose of box? So I will take romex there and then take it to AC unit.

Thanks!

 

[ghnl]

If I mount it where I wanted it above window then I will only have 3" of space above unit.

Make sure there is enough room to open the front cover & access the filter for cleaning.

If I do everything where I want it to be then my lines will be about 6-7'. I got 15' lineset. I have no flaring equipment. Should I make my best and try to shorten lines or just coil them in attic will work fine? I have unused space in attic box and cosmetically it will be just fine..

I suspect either option will work OK. A flaring tool is not expensive. Make a few practice flares before cutting the tubing. And don't forget to slide the flare nut onto the tubing before making the flare!

Are you planing to hire an HVAC tech to evacuate the lines prior to start up? He/she can easily cut the lines and make the flare connection. It'd take about 5 minutes or less.

I wonder about vibrations.

I mounted ours on concrete pads but I find they are fairly quiet and smooth.

I did not reply to your electrical questions as that is not my expertise.

 

[katit]

I will evacuate myself. I have vacuum pump and gauges for R134. I'm EPA certified too (FWIW)

Where do I get flare tools locally? Harbor Freight? I know there is different angles, etc. What kind of tool do I need for AC lines?

 

[ghnl]

I forget the flare angle off hand. I do recall it is nothing special - standard plumbing type. Sears/Craftsman has the tool, Loews/Home Depot has the tool, etc.

flaring copper tubing

 

[katit]

Spent weekend working on install.

I got condenser mounted up on a brackets next to my attic (had to replace siding so I don't have to worry about it..)

Installed disconnect on a left.

Now I have some issues:
1. I got whip of protector pipe with disconnect - to place power cable inside. Well, this tube is somewhat big, like 1" and if I use it - I won't be able to put other cable under cover on condenser. Looking at this picture - author didn't bother with protecting cables. Is that OK?

http://i476.photobucket.com/albums/rr121/thetxshrine/HPIM1808.jpg

2. I have masonry wall (block + brick). I was making 1" hole for drain tube and got stock when I reached brick. It's almost like a steel plate and I have no-go. Whatever it is - it feels like a huge PITA...


3. In order to pull lineset and install cables I had to remove drywall above AC. I will have to install it all back, tape/mud and make mess. I wonder if I shouldn't connect anything and remove wires from itnernal unit (write down where they go) and then connect internal unit when all completed? The only problem is I won't be able to test unit until all is done..


Any advice on those items?

 

[pseudorealityx]

I will evacuate myself. I have vacuum pump and gauges for R134. I'm EPA certified too (FWIW)

Where do I get flare tools locally? Harbor Freight? I know there is different angles, etc. What kind of tool do I need for AC lines?

A little late to this thread, but mini-splits are typically R-410a, NOT R-134

 

[konnerbelly]

I have had a mini split for about 3 years now. I used a 9 k btu mini split for a 400sq ft room with 2 uncooled 600 watters. It kept the room at between 75 and 79 no prob. You're golden.

 

[katit]

Need help with instruction.
http://www.ramsond.com/minisplit/74GWX/manual37-74GW.pdf

Page 20 - bleeding.

From what I understand - currently condensor valves closed and all refrigerant inside compressor/condensor.

When I hook up vacuum pump - there is no shraeder valve, right? Evap circuit all open and I will vacuum lines and evap all together.

Then step 4 they tell me to close valve on pump. I don't have one. Do they mean I have to use gauges and can't get away with just a pump?

In step 6 I need to open valve 1/4 turn. If I understand correctly it will let refrigerant into vacuumed evap and lines. Right?

And then in step 7 I will open valves allowing refrigerant flow. Does it mean that 3-way valve will shut outlet to vacuum pump at the same time I open it to evap?

Also, couple other questions:
1. Tightening lines. Will crowfoot wrenches + regular torque wrench work?
2. If I get set of R410 gauges (I need them for house unit too anyway) - will it be enough or I need other adapters/etc? They sell some adapters for mini-splits on eBay.
http://cgi.ebay.com/r410a-r-410a-MI...ewItem&pt=Air_Conditioner&hash=item5ad6ced830

3. Which gauges to get? 4-way or cheaper ones? Why would I need 4-way?
4. Is my automotive 2cfm pump be enough for mini-split?

Thanks!

 

[jm1fd]

Page 20 - bleeding.

Apply pressure to the wound.

From what I understand - currently condensor valves closed and all refrigerant inside compressor/condensor.

When I hook up vacuum pump - there is no shraeder valve, right? Evap circuit all open and I will vacuum lines and evap all together.

The service port should have a Schrader valve in it. But yes, you should be able to apply a vacuum at the service port and evacuate all the lines and evaporator.

Then step 4 they tell me to close valve on pump. I don't have one. Do they mean I have to use gauges and can't get away with just a pump?

If you turn the pump off without first isolating it from the system the vacuum in the system will **** vacuum pump oil back into the system. Big mess. DO NOT WANT.

In step 6 I need to open valve 1/4 turn. If I understand correctly it will let refrigerant into vacuumed evap and lines. Right?

Yes...looks like they just want you to let a little bit of refrigerant into the system to pressurize it so you can leak-check it with soapy water.

And then in step 7 I will open valves allowing refrigerant flow. Does it mean that 3-way valve will shut outlet to vacuum pump at the same time I open it to evap?

Looking at the diagram, it would appear that the valve only isolates the condenser from the lines and service port.

1. Tightening lines. Will crowfoot wrenches + regular torque wrench work?

2. If I get set of R410 gauges (I need them for house unit too anyway) - will it be enough or I need other adapters/etc? They sell some adapters for mini-splits on eBay.
http://cgi.ebay.com/r410a-r-410a-MI...ewItem&pt=Air_Conditioner&hash=item5ad6ced830

No idea on either of these.

3. Which gauges to get? 4-way or cheaper ones? Why would I need 4-way?

4-way guages are so you can have your refrigerant can and vacuum pump attached to the system at the same time...this allows you to be 100% sure no air gets in the charging hose when you switch it from the vacuum pump to the refrigerant can. Not necessary for a mini-split.

4. Is my automotive 2cfm pump be enough for mini-split?

Should be plenty. It may just take a bit longer than evacuating a car system.



HAH! I just noticed in your sig you have a '94 RX-7...me too! Mine is a black/tan touring.

 

[katit]

HAH! I just noticed in your sig you have a '94 RX-7...me too! Mine is a black/tan touring.

Thanks for reply, it helps. Do you just tighten connections by feel?

I got montego blue with tan/black interior PEP. Daily driving it right now.

 

[portableac7]

My research indicated that if the two units are likely to be operated separately then get two separate units. If you are conditioning a large area or different spaces of the same living area (say, living room & bedroom) then the dual unit is best.

Yes the dual unit is the best....... I have great similar experience about it last year........

 

[wood4d]

small comment... you need to get a 410 adapter to hook up to your gauges. They change fitting size so you dont add the wrong refrigerant.

 

[katit]

Yes, I bought those 1/4->5/16 also known as 1/2 adapters.