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  1. #1
    Join Date
    Jul 2009
    Posts
    26

    NEWBIE INSTALLING USED SYSTEM IN OLD HOUSE. NEED NUMBERS AND IDEAS

    Just to introduce myself, I am a mechanical engineer and installing a somewhat unknown Tempstar heatpump system in an older 1000sf home so I can sell it. The house is one story, no basement, junk insulation, junk windows, in KS, leaks like crazy. I have some general HVAC knowledge and much more in the electrical areas, good friend is a commercial HVAC designer but little help on rezzy stuff. I am looking for a fast, cheap way to climate control this old house. Right now it has a window unit and floor furnace.


    Units are Tempstar, condenser model is CH5030, min amps is 17.9A and max fuse is 30A, indicates 8500 watts cooling. furnace only tells me 75K btu input. Not much to go on. Per some others' remarks, these units are likely 2.5Ton or 1000cfm. Furnace is updraft with a 14x19 opening.


    PLAN:

    Punch hole straight down in subfloor and use stud network to create return passages and instal (2)13x19 return ducts in the lower part of the walls. Due to tight floor space, I do not want them in the floor but I realize that is easiest. I plan to get a basic plentum made for the output that is 14x19xroughtly 48 tall to extend into the attic. I will then punch multiple holes for collars to install insulated ducting for the positive venting of the home. sizing is all open right now

    Questions:

    Idea on how big these units really are?

    What should my target unit size be given the condition of this home and its climate?

    Can someone help with flow numbers for vents, insulated duct sizes, returns, etc? This seems to be my biggest problem right now. I have no idea what pressures I will or should be operating at.


    Is it best to match the flows of the returns and pos vents? I am worried about the house leaking worse if drawing in ambient air or even forcing it out.

    ALso, because my units are actually heat pump designs, would anyone advise using it as such? I have heard not to even mess with it and I planned to just use the gas furnace for heating. My understanding of them is that the flow of refrigerant is reversed thus using the A coil as a condenser which just seems poorly efficient to me....


    Any help would be greatly appreciated guys. I have to move on this project in about 3 weeks.






    EDIT********** I just read your stickies and did not realize this was a pro only forum. I guess delete if you must and I will move on. A recommendation to another forum would be a plus. Just needing some basic values. Not asking how to wire the thing in, just wanting to get a grasp on ideal flow rates and pressures.

    Upon reading some posts, this seems to be a "you can't do it unless you are a pro" site. I guess I will move on. Thanks...
    Last edited by viper1; 07-30-2009 at 03:04 PM.

  2. #2
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,326
    Quote Originally Posted by viper1 View Post
    this seems to be a "you can't do it unless you are a pro" site.
    You can do it -- question is how WELL can you do it? Your post above indicates large gaps in your knowledge base to make what you want actually work WELL. You might get it all together and the thing starts and runs...but how WELL will it start and run?

    That's the difference between an amateur and a pro.

    Leaky house with cheap windows and marginal insulation and used central equipment - probably better off sticking with window unit and floor furnace. Take the loss on the sales price vs. throwing money down the drain on used equipment installed with shaky knowledge.
    • 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.

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