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  1. #1

    Confused Help with Mini Split plz!!!

    I know the terms of service on this site are no DIY and I understand why but no contractor will install the mini split i have in my new home. I can not install the outside condensor unit outside (not possible in this location) it must go in an attic area facing out a window or in a large well ventilated crawl space. No one will do this for me even though it is a small 9000 btu unit (w/heat pump). I can wire it np and I purchased a precharged lineset (it doesn't use freon its the new stuff). My question is, if I just hook up the linset without vacuuming the system, will I break anything or just notice some decreased performance? At this point I just want to hook the damn thing up and be done with it. Do I absolutely have to have the lines vacuumed? People seem to be helpful here so if anyone could just plz let me know if Im going to burn my house down or blow up my AC that would be great!

  2. #2
    Join Date
    Mar 2007
    Location
    Orange County NY
    Posts
    211
    This is a May fools joke right?
    I'm not falling for this one!!!

  3. #3
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Where are you located? I'll do it for 5 G's....

  4. #4
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634
    Quote Originally Posted by bigwurzz View Post
    I know the terms of service on this site are no DIY and I understand why but no contractor will install the mini split i have in my new home. I can not install the outside condensor unit outside (not possible in this location) it must go in an attic area facing out a window or in a large well ventilated crawl space. No one will do this for me even though it is a small 9000 btu unit (w/heat pump).
    There's a reason they refuse to install it like that -- it won't work. Condensing units require substantial amounts of air. a 9,000 BTU unit requires about 900 CUBIC FEET of air PER MINUTE. Try to picture just how big this really is.

    For a visual example:
    1 cubic foot = 28.3 liters. Think about that, just ONE cubic foot = 14 2-liter soda bottles. 900 cubic feet = 12,735 2-liter bottles. Do you really have room to store that many soda bottles in your attic or crawlspace? Do you have enough room to move THAT many bottles EVERY SINGLE MINUTE the system's running? The unit needs to go outside.

  5. #5

    No im serious

    Really, I want to know if this is possible. The unit cant put off that much more heat than a portable unit. the attic is huge it would blow out an open window or the crawl space is an option. Just cant have it outside.

  6. #6

    K What about vacuum pump

    Do I need to vacuum the lines with a precharged lineset??

  7. #7
    Join Date
    Oct 2003
    Location
    UTAH
    Posts
    145
    Quote Originally Posted by bigwurzz View Post
    Do I need to vacuum the lines with a precharged lineset??
    Not unless they have accumulated a lot of debris on them.

  8. #8
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634
    Quote Originally Posted by bigwurzz View Post
    Really, I want to know if this is possible. The unit cant put off that much more heat than a portable unit. the attic is huge it would blow out an open window or the crawl space is an option. Just cant have it outside.
    I'm being 100&#37; serious. Rule of thumb is that a condensing unit will have a fan which blows approximately 10% CFMs as it has BTU capacity. I just pulled up the service manuals for Fujitsu mini-splits (not sure which brand you have, not too many have systems < 18000 BTUs) and here's what they say:



    So my figure of 900 is actually LOWER than what the unit needs. With the new number, go make room for 17,135 2-liter bottles in your attic... PER MINUTE.

    If you want to ruin a perfectly good mini-split and prevent it from cooling the space properly (the heat has to go somewhere), then install it in the attic. When you room is hot and the unit eventually shoots itself in the foot from not being able to rid itself of enough heat, don't come crying to us...or any of the other contractors who told you it won't work. Put the damn condensing unit outside where it belongs. Besides, if you attempted to put it in the attic gable or similar, you'd be depressurizing the house, which is going to bring in hot, unfiltered air through all of the cracks & seams of the building, which is going to defeat the purpose of having air con.

    I'm not trying to be a pain in the ass... I can't change the laws of physics.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,774
    Your attic may be large. But how hot does it get in the attic in the summer.
    Might get hot enough to make your 9000 btu into a 3000 btu unit.

    A 9000 btu condenser will rejsct 9000 btu's from the house plus around 2800 btu's from the compressor and condenser fan. So it won't take long to heat up your crawlspace.


    You can install this yourself with out a vacuum pump.
    Hopefully you can afford to buy a new condenser every month or so if you install it in the attic or crawlspace.







    Any reason it can't be intalled on the roof.
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  10. #10
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,086
    If the condenser can't go on the ground, how about a bracket attached to an outside wall? Do you have a ridiculously restrictive HOA that won't let you put the condenser on the ground? If so, I'd be sorely tempted to tell them to eat fecal matter.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  11. #11
    Pre charged lines? Been a long time since I heard this.

    let me tell you that your unit is precharged and if you have precharged lines then you will be overcharged.

    Once again a great deal on the unit is turning into not such a great deal in the end.

  12. #12
    Join Date
    Aug 2006
    Location
    Chelmsford MA
    Posts
    1,518
    Gotta love it! He starts out saying "I know the terms of service on this site are no DIY and I understand why" But then goes right into asking how he can get this installed himself! Never ends.
    We only want to do it, if we can do it right.

  13. #13
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,007
    This one ends here.
    Perhaps you should have read the instructions before calling.

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