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  1. #1
    Join Date
    Sep 2008
    Posts
    582

    I think it will work

    I have a .75hp OD condensing unit, nicely built, headmaster, LPCO, HPCO, etc.

    I need a .25hp setup, any reason why I couldn't just change the compressor?

    Will the over sized condensor & receiver create a restriction due to volume?

  2. #2
    Join Date
    Aug 2006
    Location
    st.petersburg,fl
    Posts
    803

    Lightbulb

    Need more information...

    How long is the run...

    Refrigerant...

    Size of the equipment...

    Reason I ask is that what you have may be too much for the .25 and you may need a .50 in which you would get away with...

    Hope this Helps...
    Isn't sanity just a one-trick pony anyway? I mean, all you get is that one trick, rational thinking, but when you're good and crazy, well, the sky's the limit!

  3. #3
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,326
    I've done similar to this numerous times with very good results. The main difference is the discharge pressure will be lower because of the oversized, 3/4 HP condenser and therefore the compressor will have a little more capacity than it would with a 1/3 HP condenser.

    Typical refrigeration condensing units run at about a 30+F TD (T condensing - T ambient), so I would expect this unit to run at around a 10F TD. At a 90F ambient, the SCT would be approximately 100F. Take this into account when selecting a compressor to match your design load.

  4. #4
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    474
    Im curious if you do something like this will the oversized condenser need more refrigerant backed up by the headmaster in the cold winter months to mantain a minimum head pressure?

  5. #5
    Join Date
    Feb 2004
    Location
    Western New York
    Posts
    1,047
    Quote Originally Posted by dangpgt97 View Post
    Im curious if you do something like this will the oversized condenser need more refrigerant backed up by the headmaster in the cold winter months to mantain a minimum head pressure?
    Yes, because the extra refrigerant charge is determined by the volume of the condenser, along with the lowest ambient temp for your area.
    Experience is what you have an hour after you need it.

  6. #6
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,326
    Quote Originally Posted by dangpgt97 View Post
    Im curious if you do something like this will the oversized condenser need more refrigerant backed up by the headmaster in the cold winter months to mantain a minimum head pressure?
    Quote Originally Posted by baub View Post
    Yes, because the extra refrigerant charge is determined by the volume of the condenser, along with the lowest ambient temp for your area.
    That's a very good question.

    In this case, the condenser would be about three times the size that of a "normal" system, so the total volume would be greater in about the same proportion. It would follow that the volume required to flood the condenser at lower ambients would then be greater.

    If you want to try your hand at the hand calcs of such a questions, here's the Sporlan methodology:

    http://www.sporlanonline.com/90-30-1.pdf

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