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  1. #1
    What does it do to upsize an indoor evap coil.

    Example: 3 Ton condenser

    4 Ton Evap coil

    Does this increase the Seer rating?

    Do you have to change the orifice size?


  2. #2
    Join Date
    Jun 2003
    Hell Hole Swamp
    Originally posted by vapor_rush
    What does it do to upsize an indoor evap coil.

    Example: 3 Ton condenser

    4 Ton Evap coil

    Does this increase the Seer rating?

    In many cases yes, many higher SEER units have a larger indoor coil, provided the manufacturer lists the coil/outdoor unit as a match.

    Do you have to change the orifice size?

    Yes, if it has a fixed orifice metering device it must be sized to the outdoor unit

  3. #3
    Join Date
    Jul 2002
    Zelienople, Pa
    1st, you need to look into that particular piece of equipments spec book to see if its matched.
    I know on my personal system I have a 2 ton heat pump w/ a 3 ton coil because I can get around 15 1/4 SEER from it.
    How tall are you Private???!!!!

  4. #4
    Join Date
    May 2000
    Indianapolis, IN, USA
    Increased SEER, decreased latent capacity meaning higher humidity. Not something to do in a humid climate though many manufacturers do it rather than use a TXV on "normal" sized coil.

  5. #5
    Join Date
    Mar 2002
    Richmond, Virginia
    There have been many discussions about the pro's and con's of over and undersizing coils. Try the search feature above for hours of reading.
    There is nothing more frightful than ignorance in action....Mark Twain

  6. #6
    Join Date
    Jan 2005

    Question Oversized indoor coil

    BaldLoonie. So per the example
    if I went with the 4 ton coil
    with a 3 ton condenser with
    a txv will this give a substantially
    higher seer with out loosing
    to much latent capacity?
    When I first got into this trade
    the guy I worked for did this
    a lot. Minus the txv.He did not
    no why he would go a half to one
    ton over size on the indoor coil
    just that thats what his dad
    taught him to do.And they never
    had any problems.He would use
    a txv only if the whole system
    scared him.Retro fit job big
    house lousy ducting and it
    had "alot of glass you know"
    and with the hot afternoon sun
    and all! I learned a lot from this
    guy NOT because he was very good
    OR knowledgeable.Bot because
    he would take me to a job and
    say "this is what I was thinking"
    but do what you want to.Get
    what you need from the supply
    house.Then thereI would be
    in front of the customer.....
    Put a lot of pressure on me.
    But I have a strong need to not
    only be right.But right the first
    time.That and I just hve to do
    right by the customer.

  7. #7
    Join Date
    Aug 2003
    We oversize just a half of a ton I haven't looked into it but I was told that it wasn't good to oversize a hole ton but sometimes we do.This would be a good question for NormChris.

  8. #8
    Join Date
    Jan 2002
    Lennox 36HC coil /w/txv on Lennox Horizontal Gas Furnace with American Standard 12.0 S.E.E.R. CONDENSER

    I drop my electric bill in summer 65.00 a month from
    10.0 s.e.e.r lennox 36acb change -out 2003
    'Life begins with the journey each day'

  9. #9
    Join Date
    Feb 2005
    In a van by the river
    Something else to keep in mind is to make sure you have a sufficient size blower in that furnace or else coil will freeze
    ## + years in the field never made you a know-it-all This industry is far more diverse than you are

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