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  1. #1
    Join Date
    Sep 2002
    Posts
    511
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    I am using 160 sq.in. per ton for return air sizing.

    example: 4ton x 160sq.in. = 640sq.in........25"x25"Return Grill.

    Is this right? are there other ways to figure return air grill size?

  2. #2
    Join Date
    Feb 2004
    Location
    southern illinois
    Posts
    5,536
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    IS THIS FILTER GRILLE?

  3. #3
    Join Date
    Jul 2002
    Location
    Zelienople, Pa
    Posts
    2,965
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    filter grills = 200 sq. inches surface area per ton.
    How tall are you Private???!!!!

  4. #4
    Join Date
    Sep 2002
    Posts
    511
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    Yes,I was using a filter grill as an example.

    BoltonNC, you say 200 sq.inches per ton.

    Does that apply to heat pump applications also?

    I have a co-worker who told me that he has always been taught that heat pumps require more return air than just a regular split system,is this true.

    I will start using the 200 sq.inche method,more is better.

  5. #5
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
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    For filter grills,200 sq. in. per ton or 300 fpm velocity,works out the same.Less restrictive,quieter,and better filtration.

  6. #6
    Join Date
    Nov 2001
    Location
    East Texas
    Posts
    996
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    CFM/2 = sq.inches of area.

    2 ton 800/2 = 400 sq.inches
    3 ton 1200/2 = 600 sq. inches
    4 ton 1600/2 = 800 sq. inches
    5 ton 2000/2 = 1000 sq. inches

    Easier for me to remember for some reason. Same as Dash has stated.

  7. #7
    Join Date
    May 2004
    Posts
    39
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    Don't we use Duct chart any more ladies. Go purchase one and calculate out the grill size. What we all say was "the rule of thumb", which we know is not very accurate.

    Have fun

  8. #8
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
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    Originally posted by stef
    Don't we use Duct chart any more ladies. Go purchase one and calculate out the grill size. What we all say was "the rule of thumb", which we know is not very accurate.

    Have fun
    Ductolator,300 fpm,is the same size as 200sq. in. per ton.i use the ductolator,but either way is okay.

  9. #9
    Join Date
    Jan 2004
    Posts
    111
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    s

    [Edited by hvac solutions on 02-25-2005 at 08:42 AM]

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