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  1. #14
    Join Date
    Feb 2006
    Location
    Somewhere in the midwest
    Posts
    405
    No. Not that one. The one I posted had graphs and was set up as a power point. I still have it but can't remember how to post it. It has been a while since I posted pics and power points. Help me and I will send it to you.
    Sound installation practices is the key to success. Equipment is only as good as the person installing it.

    If I can't fix it, it ain't broke.

  2. #15
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,793
    Wow. Blackmail. If you don't help, I won't send it to you.

    I don't know how to post a PP file.
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    How many times must one fix something before it is fixed?

  3. #16
    Join Date
    Feb 2006
    Location
    Somewhere in the midwest
    Posts
    405
    Very funny. You are quite witty Beenthere.. Well, you have the info anyway. I just did not remember how to do it. No biggie. It has been a helpful sales tool by poor saps who can't talk homeowners into doing the right thing. I am no salesman. If I don't like the looks of something, I don't do it. Money is not not worth reputation to me.
    Sound installation practices is the key to success. Equipment is only as good as the person installing it.

    If I can't fix it, it ain't broke.

  4. #17
    Join Date
    Dec 2007
    Location
    Stockton, Ca.
    Posts
    33

    13 seer cond to 10 seer evap

    One thing you are also over looking with a mismatched system unless you have a reciever is flodback to the compressor, so you end up having compressor failure. But you get the efficiency loss due to the fact a 13 seer requires more refrigerent than a 10 seer of the same tonage which usually floods the evap and the cooling occurs in the "changing of state" of the refrigerent in the evap coil. With a properly sized evap it is large enogh to accomodate the additonal refigerent so the change of state" occures within the coil like it is supposed to and everything works fine. As for air flow, too much air and you decrease moisture removal "laten heat" and to little air flow and you decrease sensible heat removal but increase laten heat removal. Typicly air flow is between 350 to 450 cfm per ton average of 400 cfm per ton.

  5. #18
    Join Date
    Apr 2007
    Posts
    6,285
    If the duct system is designed right

    Looking at a 1 1/2 ton unit right now....it's got a 14,000 btu compressor in it....with much larger coils.

    TXV would help straight a/c if you must do it....

    Heatpumps are a no no.

  6. #19
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,793
    Receiver won't help.
    An accumilator would help alittle.
    But, thats just Mcgievering a crap system though.
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    How many times must one fix something before it is fixed?

  7. #20
    Join Date
    Dec 2007
    Location
    Stockton, Ca.
    Posts
    33

    13 seer to 10 seer evap

    My bad I got it bass ackward... sorry... was typing faster than I was thinking...

  8. #21
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,793
    happens to everyone.
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    How many times must one fix something before it is fixed?

  9. #22
    Join Date
    Dec 2007
    Location
    East central Indiana
    Posts
    477
    That Bristol report is definitely a good selling point for a penny-pinching customer who doesn't want to change out the coil.

    But, on the other hand, say your back was against the wall (eg, height restrictions, etc). Could you put a smaller piston on a 3 ton 10 SEER coil and use either a 2 ton or 2.5 ton 13 SEER unit, and then reduce the blower speed (ie, the "blue" speed instead of the black) to avoid the dehumidification problem that beenthere mentioned (BTW, all this latent/sensible heat stuff makes my head spin!)?

  10. #23
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,793
    If the old unit was barely able to keep up.
    After down sizing the piston, the new unit won't keep up.

    Don't forget.
    Their are third party coil manufacturers, that make shorter height 13 SEER rated matching coils for most if not all brands of condensers.
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  11. #24
    Join Date
    Apr 2007
    Posts
    6,285
    The piston that comes with the unit should be used inside. A TXV would be better.

    Up sizing 1/2 ton can add back some of that capacity on a straight a/c system. Your pressures will already be low due to an oversized outdoor coil and an undersized inside coil.....dropping the airflow could be horrible.

    As beenthere said unless your MCgiever....


    Ill add or Hamburglar...
    Last edited by BigJon3475; 07-17-2008 at 06:08 PM.

  12. #25
    Join Date
    Dec 2007
    Location
    Stockton, Ca.
    Posts
    33

    Hmm 13 seer cond to a 10 seer coil

    then you may have an under sized system if you go with a smaller cond. You really need to just change both the cond and coil and solve the problem and be done.

  13. #26
    Join Date
    Jul 2006
    Posts
    613
    Quote Originally Posted by beenthere View Post

    If the old 10 SEER system was moving the proverbial 400 CFM per ton. You now have high humidity, and maybe some mold growing in the ducts, and other areas of the house.
    Because the evap coil temp is too high.

    And, after mold remediation, you still need a new indoor coil or air handler.
    I know this is and an old post, but I think I have proof that BT is correct.

    Around 2.5 years ago my 12-14 yr (matched with AHU) 10 SEER 2.5 ton HP OD unit died. I replaced the OD unit with a 13 SEER unit, but left the original AHU installed. It did function, but we were cold on the cold day's and HOT on the hot day's, with huge electric bills.

    The entire HP unit was replaced with a half ton larger 15 SEER system 2 weeks ago. The comfort so far is like night and day compared to the old unit.

    I have pictures of the old AHU coil. Dried Mold! (according to the installer) 1/4" bubble looking things, black and dried covering return side of the evap coil. I have pictures that I can post, they are gross looking.

    The duct's are scheduled to be cleaned!

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