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  1. #1
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    Default HVAC Size? - Preston's guide?

    Does anyone have a preston's guide or can you tell me the size of these? I need a size on a Rheem heat pump system and can't wait for Rheem to get back to me - I want to finish this report. Thanks!

    Condensing unit:
    Model RPLA-041JAZ
    Manufactured in 2003

    Air Handler:
    RBHK-24J11NFF
    Manufactured in 2004

    24 in the air handler clues me in that it might be a 2 ton system
    The RLA on the condensing unit was 21, so it doesn't make sense.

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  2. #2
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    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by Matthew Barnicle View Post
    Condensing unit:
    Model RPLA-041JAZ
    Manufactured in 2003
    3-1/2 ton

    Air Handler:
    RBHK-24J11NFF
    Manufactured in 2004
    You need the number on the coil, not the number on the AHU itself. With only this number you may need to wait for Rheem, but they may ask for the number on the coil as different coils can be installed into the same AHU cabinet.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  3. #3
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    Default Re: HVAC Size? - Preston's guide?

    Rheem just got back to me -
    Condensing unit - 3.5 ton
    Air handler - 2 ton (Rheem did not ask for the number on the coil)
    Doesn't surprise me - this house was a real piece of work.


  4. #4
    Sam Rao's Avatar
    Sam Rao Guest

    Default Re: HVAC Size? - Preston's guide?

    Is Preston's guide the only reference for HVAC specs? Does it cover specs for commercial HVAC systems?

    Thanks,
    Sam


  5. #5
    Darrell Udelhoven's Avatar
    Darrell Udelhoven Guest

    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by Matthew Barnicle View Post
    Rheem just got back to me -
    Condensing unit - 3.5 ton
    Air handler - 2 ton (Rheem did not ask for the number on the coil)
    Doesn't surprise me - this house was a real piece of work.
    A 3.5-Ton A/C on a 2-Ton air-handler.

    Better have a Manual D done to see if there is enough available static pressure!

    It looks like there could be some airflow problems with that situation.


  6. #6
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    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by Matthew Barnicle View Post
    Rheem just got back to me -
    Condensing unit - 3.5 ton
    Air handler - 2 ton (Rheem did not ask for the number on the coil)
    Doesn't surprise me - this house was a real piece of work.
    I'll have to double check but I think Rheem gave you some bad info on the air handler.
    They don't rate their air handlers with the nominal capacity in the model number.
    It only means it's a 24" wide air handler.

    Measured Performance more than just a buzzword

  7. #7
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    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by DavidR View Post
    I'll have to double check but I think Rheem gave you some bad info on the air handler.
    They don't rate their air handlers with the nominal capacity in the model number.
    It only means it's a 24" wide air handler.
    Rheem and Ruud put that on the nameplate on the evaporator coil itself, not on the air handler nameplate.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  8. #8
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    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by Jerry Peck View Post
    Rheem and Ruud put that on the nameplate on the evaporator coil itself, not on the air handler nameplate.

    They put them on certain older models as well.

    For instance and RBHC-14J would match up to a 1.5 ton and 2 ton unit while an RBHC-17J would match up to a 2.5 ton to a 3 ton unit and so on. The 14 and 17 were the widths of the air handler cabinets or coil casing.

    When 13 SEER became the norm these numbers changed around but to m knowledge they have always been on the air handler nomenclature as well.

    Measured Performance more than just a buzzword

  9. #9
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    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by DavidR View Post
    They put them on certain older models as well.

    For instance and RBHC-14J would match up to a 1.5 ton and 2 ton unit while an RBHC-17J would match up to a 2.5 ton to a 3 ton unit and so on. The 14 and 17 were the widths of the air handler cabinets or coil casing.

    When 13 SEER became the norm these numbers changed around but to m knowledge they have always been on the air handler nomenclature as well.

    All I know is that I always had to, while the cover was open (I presume we are all opening those covers) look at the nameplate on the coil as that was where the size of the coil was stated.

    Various cabinets could take various coils, but you know all that information much more than I do, I was looking for the sizing.

    The one in the attached photo is a 2-1/2 ton, A030S. This is for others to know where to look for the sizing on Rheem and Rudd.
    (Yeah, that obviously had a bit of rust on it. )

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    Jerry Peck
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  10. #10
    Darrell Udelhoven's Avatar
    Darrell Udelhoven Guest

    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by DavidR View Post
    They put them on certain older models as well.

    For instance and RBHC-14J would match up to a 1.5 ton and 2 ton unit while an RBHC-17J would match up to a 2.5 ton to a 3 ton unit and so on. The 14 and 17 were the widths of the air handler cabinets or coil casing.

    When 13 SEER became the norm these numbers changed around but to my knowledge they have always been on the air handler nomenclature as well.
    You are correct; the 24 is the width, not the tonnage.

    Also, the 24 width takes a 4-ton coil.
    RCHJ-48A1GH24

    Therefore, it is probably rated a 4-Ton air handler, - which would be a match for the 3.5-Ton condenser.

    I don't know why the Rheem folks would say it was a 2-ton AH.

    Last edited by Darrell Udelhoven; 10-16-2009 at 07:43 PM. Reason: deleted a word

  11. #11
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    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by Jerry Peck View Post
    All I know is that I always had to, while the cover was open (I presume we are all opening those covers) look at the nameplate on the coil as that was where the size of the coil was stated.

    Various cabinets could take various coils, but you know all that information much more than I do, I was looking for the sizing.

    The one in the attached photo is a 2-1/2 ton, A030S. This is for others to know where to look for the sizing on Rheem and Rudd.
    (Yeah, that obviously had a bit of rust on it. )
    Thank goodness they made it easier when the switch to 13 SEER was made, now they have the capacity and width in the model number of the air handler.

    Why they didn't do this before is a mystery to me Jerry.
    They like to keep us guessing.

    Measured Performance more than just a buzzword

  12. #12
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    Default Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by Darrell Udelhoven View Post
    You are correct; the 24 is the width, not the tonnage.

    Also, the 24 width takes a 4-ton coil.
    RCHJ-48A1GH24

    Therefore, it is probably rated a 4-Ton air handler, - which would be a match for the 3.5-Ton condenser.

    I don't know why the Rheem folks would say it was a 2-ton AH.

    Good to see you over here Darrell.

    Measured Performance more than just a buzzword

  13. #13
    Darrell Udelhoven's Avatar
    Darrell Udelhoven Guest

    Smile Re: HVAC Size? - Preston's guide?

    Quote Originally Posted by DavidR View Post
    Good to see you over here Darrell.
    I was also glad to see you on this forum David.

    You are a fantastic contributor to other major forums. - Darrell


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