"Another" mini-split question(s)

[Rosco]

I have been doing my research for about a year now on mini-splits for my bonus room above my garage. After getting several quotes from local HVAC installers, who do not really "like" mini-splits (they all want to sell me a ducted system) i have decided to install it on my own. Here are a few details to answer questions that might come my way;

- the bonus room is designed for a mini-split system since there is not enough room for the ducted system with all of the duct work

- I have used many calculators and even had the contractors figure it, comes out to 16 - 18,000 btu (depending which one I use)

So based on the decision to go with a mini-split, and all of the options available I have it narrowed down to two.

http://www.goductless.com/Mitsubishi-Mr-Slim-mitsubishi-air-conditioner-p/11029.htm

http://www.goductless.com/LG-Air-conditioner-Ductless-Mini-Split-Heat-Pumps-p/11400.htm

Questions;

- How hard is it to pull the vacuum myself? I only need 25' of linset and the mitsubishi model claims it will not need to be re-charged if not going over 25'. I know I will have to have it checked eventually.

- Can the linset lines (1/4 and 1/2) be routed separately from the drain line? I would like to run the linset lines over my stairwell (indoor unit will not be on an outside wall) and the drain separately for constant flow. The linset lines would actually run about 12" above the unit for about 4' of stairwell width.

- Are there any significant differences between the two models listed?

- Is it worth the additional investment to buy a vacuum pump and guages?

BTW, have not found a contractor that is crazy about doing the vacuum/charge etc. on a unit they do not install....is this the norm?

Thanks in advance for any/all advice. Sorry for the long winded post, been a frustrating day

 

[rickairmedic]

Rosco either of those units will be good units. On your pulling the vacuum issue look around your local pawn shops for used vacuum pumps and Guage sets also check craigslist for these items. Most likely your best bet on finding someone to do the vacuum/charge would either be to get a guy to do it on his off time oer find a small ( one owner type shop ).


Rick

 

[theoldwizard1]

A lot guys "moonlight" especially in the "in between seasons". Forget getting any outside help after June 1.

 

[ghnl]

I installed my own units (one for garage, one for bonus room above).

- How hard is it to pull the vacuum myself? I only need 25' of linset and the mitsubishi model claims it will not need to be re-charged if not going over 25'.

If you have a vacuum pump and appropriate fittings it is not hard. I paid an HVAC tech to do it for me. Yes, they were not thrilled about doing it on a system they didn't install but I was already a 'steady' customer - I pay them to do annual maintanance on our house system. If I had the forethought to plan the mini-split install for just before the house was due for service I think it would have been easier/cheaper (one visit charge plus a little extra time)

- Can the linset lines (1/4 and 1/2) be routed separately from the drain line?

Should be no problem. The drain is best if it can empty via gravity (simple and nearly fool-proof). It is possible to have a pump drain but then you have an extra item to break down...

 

[rickairmedic]

I will ad to my earlier post . You are going to have $200.00 + into a vacuum pump and guages from a pawn shop so another option is simply to pull over when you see an HVAC company van and offer the guy $200.00 to pop over on a saturday morning and pull a Vacuum and charge it ( as long as he doesnt need to ad refrigerant ) .

Rick

 

[Rosco]

excellent replies. i will definitely look into the side job part as this time of the year in Ga they are everywhere.

I will definitely run my drain separate for a better gravity drain.

thanks!

 

[dlewis]

acwholesaler.com has the same unit a little cheaper

 

[Rosco]

where is a good source for vacuum pumps and guages (new). I think a few of us are going to chip in on a reasonable set. Also, what CFM do I need, and will the same unit work on a car?

 

[Rosco]

After searching for all of the tools/equipment etc. to do it myself I called the sales company and found out that in order for the warrantee to be valid I must have it hooked up, vacuumed, and charged to specs by a licensed HVAC company.

OK, for the Mitsubishi 7 year compressor/5 year parts warrantee I think it is a valid request. Found a local company to do the complete install for $800 if I purchase all parts. Does this sound reasonable? I sure do not want to spend $2,000 on the mini-split and associated hardware and not have a warrantee, or screw something up because I think I can do anything......

Any inputs?

 

[rickairmedic]

Rosco $800.00 is reasonable to install your equipment considering they are not making any ( markup money ) on the equipment .Remember I told you to find a Tech and offer him $200.00 to pop over on a saturday ( after you had it installed ) to do the vacuum and startup. The company he works for has ALOT of overhead they have to pay for plus payiong him so yes $800.00 is reasonable .


Rick

 

[Rosco]

thanks, I have gone the route of doing things myself only for it to cost me more in the long run......

I figure part of the price is also taking into consideration liability and warrantee work.

 

[rickairmedic]

Rosco one way of looking at it is if the compressor takes a poop you will spend that $800.00 to replace it without the warranty . I am a strong DIYer and have pretty much rebuilt my house from a fire last year by myself SWMBO has done alot herself. She layed all of the tile in the bathroom as well as most of the repainting . I had to gut the basement pressure wash it and repaint it as well as replacing most of the floorjoists ,subfloor and flooring on one side of the house. I installed all new plumbing ( waterlines and waste) as well as a new tankless water heater and complete HVAC system including ductwork ) I own an HVAC company with SWMBO . I have also completely rewired the whole house in the process . I have freinds who are master electricians and plumbers and did get them to check my work in their areas ( now I owe them favors ) .


Rick

 

[Rosco]

Great point. May I bother you for another question? I will run the power to the unit and plan on using a roll of 10/3 that I have. Based on the specs below, will the 10/3 work? Will I need all 3 wires or just 2? I also have a roll of 12/2 if that will work. Should I try a separate post in the electrical section?

Technical Specifications
------------------------------------
Cooling Capacity 17,200 BTU
Heating Capacity (BTU) 21,600 BTU
HSPF 10

Efficiency 19.2 Seer
Voltage 208-230 1 Phase
Line Set Size 1/4" & 1/2"
Max Breaker Size 15 Amp
Maximum Line Set Size / Maximum Rise 65ft / 40ft

Sound Level


- Indoor Unit 28,33,38 dB
- Outdoor Unit 54 dB
Outdoor Unit Dimensions 33-1/16"W x 33-7/16"H x 13"D
Indoor Unit Dimensions 31 7/16"W x 11 5/8"H x 9 1/8"D

Weights


- Indoor Unit 22 lbs
- Outdoor Unit 119 lbs
Total Shipping Weight 141 lbs

 

[rickairmedic]

15amps the 12/2WG will be just fine . No need for the 10/3 as you dont need a neutral .


Rick

 

[Rosco]

Found some 10-2 and ran that to the 30A disconnect (it is about a 50' run). Will tape the white wire on the ends with black electrical tape to mark it. Unit calls for a 15A breaker, since it is 208-230 i am assuming a 15A double pole.

Should I run 10 guage stranded or solid from the 30A diconnect box to the unit? I have both if one is better.

 

[rickairmedic]

Rosco you should be able to get a whip at Home Depot or Lowes that is already made up to run from the disconect to the unit . You can make up your own whip and I prefer stranded wires going to the unit itself if you decide to do that.

Rick

 

[Rosco]

Thanks. I do have one (6') from Lowes that I just bought today. I am assuming the rest of my wiring is OK?

 

[rickairmedic]

Yep everything else sounds good to me from what I read .

Rick

 

[mpire]

where is a good source for vacuum pumps and guages (new). I think a few of us are going to chip in on a reasonable set. Also, what CFM do I need, and will the same unit work on a car?

Harbor Freight?

 

[rickairmedic]

Harbor Freight?

The only guages you will find at Harbor freight are for 134A and I think before I picked up a Vacuum pump from them I would buy a decent used one from a pawnshop or evilbay. I actually have a vacuum pump I picked up on evilbay for less than $100.00 with shipping I have been using for years and I use it more than once a year .


Rick

 

[Jackfre]

After searching for all of the tools/equipment etc. to do it myself I called the sales company and found out that in order for the warrantee to be valid I must have it hooked up, vacuumed, and charged to specs by a licensed HVAC company.

OK, for the Mitsubishi 7 year compressor/5 year parts warrantee I think it is a valid request. Found a local company to do the complete install for $800 if I purchase all parts. Does this sound reasonable? I sure do not want to spend $2,000 on the mini-split and associated hardware and not have a warrantee, or screw something up because I think I can do anything......

Any inputs?

Mini-splits are typically excellent equipment. When they are not properly installed they are a nightmare. $800 is, in my opinion, a fair price for a contractor to come out and do the work and get you a warranty. One thing on the MS. Don't over size the unit. I don't know what your space is, but I have found these pretty much always exceed your expectations. With modulating equipment, how low it will go is often more important, from a comfort standpoint, than how high it will go.

Of the two manuf you reference I'd buy the Mitsu every time.

 

[Rosco]

Agree, thanks for the input. Kinda hard to throw down 800 dollars on something I am sure I could do myself......... but if anything is wrong with the unit "and" ensuring the 5/7 year warrantee is good it seems like a good investment. Plus, I do not have the tools or experience to vacuum or charge the unit. I have heard with 410 it is extremely critical. A couple months from now my ADD will have me working on something completely different and I will forget how much I spent

I had the area calculated by 3 separate contractors and also used several on-line calculators. My sizes were between 16 to 18,000 BTU. It is a bonus room in south georgia, black shingles, and has two 8' wide, 8' cieling hieght dormers that are being used for a bathroom and a closet. That is why I finally went with the Mitsubishi unit that is rated at 17,200 BTU cooling. The heat in a bonus room down here from May-Sep is killer, plus I need the capacity to cool/heat the room from the start as it will not be used all the time.

Again guys, thanks for all of the great knowledgeable advice!