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  1. #1
    I am getting various bids to replace the downstairs A/C system on my house. It's hard to compare them because I'm getting a bunch of conflicting info about sizing.

    The guy I had out yesterday told me that a) my 3 ton unit was too big for the 1300 sq. foot. downstairs, and b) that my evaporator coil and condenser were mismatched (1.5 vs. 3 ton). He recommended going down to a 2.5 ton unit, and because of the mismatch he recommended changing the coil out as well. Of course from there it didn't take long before he recommended doing a full system replace "with the furnace thrown in for free if you get our premium unit."

    Questions:
    -- I've lived in this house for 18 years and have not noticed any ill-effects due to the supposed excessive capacity downstairs unit. In particular, no short cycling. Should I downsize to 2.5 tons, which would be the same size as my upstairs unit? I've read some of the other posts, and I know that square footage doesn't tell the full story. If there's another factor which caused the initial system to be spec'ed at 3 tons, I'm worried that I may regret downsizing.

    -- And what about the fact that I've supposedly been using a 1.5 ton coil (Lennox C16-21-00-1) all this time? How important is it that they match? Again, I haven't noticed any ill effects, and I'd rather not mess with the inside stuff if I don't have to. It seems to me that if I *do* downsize the outside unit to 2.5 tons, then at least I'll be making positive progress by reducing the amount of mismatch!

    Any advice appreciated...

    Kiteflyer

  2. #2
    P.S. Another piece of relevant info: I live in Austin, Texas. It gets hot and humid here (but not as humid as Houston!)

  3. #3
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,727
    get rid of the c-16 coil just because it will start leaking soon if not already. go for matched system. if furnace is same age i would consider replacing that also due to the fact that is a lot cheaper to do it all at once than to come back and make duct work changes a second time

  4. #4
    Join Date
    Jul 2004
    Posts
    322
    Don't forget to apply for the Austin Energy rebate.
    http://www.austinenergy.com/Energy%2...bateLevels.htm

  5. #5
    Join Date
    Jun 2003
    Location
    Hell Hole Swamp
    Posts
    4,180
    Lennox in the past used model numbers that differed from other brands as far as determining the capacity, perhaps they were not familiar with Lennox and misinterpreted the size, I dont think a unit that grossly mismatched would have lived 18 years with no ill effects, if possible post the model numbers here.

    Regardless, if you replace the outdoor unit have a matching indoor coil installed as well

  6. #6
    Its not likely that you actually have a 1.5 ton coil with a 3 ton coil,maybe they are getting the numbers wrong on the one you have a set-up like this should have died a long time ago, that mis-match should have drained the oil out of the compressor and killed it.

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,875
    Can you post the m#s of your outdoor units.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  8. #8
    Join Date
    May 2001
    Location
    Kansas City
    Posts
    2,729
    I have heard of people putting in smaller coils in Texas, but it has to have a TXV. Dehumidify's better.
    CB: better to put in a complete system, just get 3 bids unless you have a very good referal from somebody you know.

    Eddy think you got it backwards, its 3 ton condenser- 1.5 ton evaporator.

  9. #9
    I appreciate all the responses. For those who asked, here are my current model numbers.

    Outdoor unit: Lennox HS22-411V-2P.
    Evap. Coil: Lennox C16-21-00-1

    I didn't mean to imply that these systems had been in place for the full 18 years I've been in my house. Only that I've been using a 3-ton outdoor unit the entire time. The entire system was replaced in 1990 when the above units were installed.

    Proposal 1 is to replace outdoor condenser with an HS27-030 (2.5 ton) and the coil with a BV13448.

    Proposal 2 is to do a full system replace with an 2.5 ton HSXA-15.

    Thanks,

    CBKiteflyer

  10. #10
    Is anybody able to confirm that I do indeed have a 3 ton/1.5 ton mismatch based on the model numbers I posted above?

    Thanks!

  11. #11
    Join Date
    Oct 2004
    Posts
    3,400
    Originally posted by cbkiteflyer
    Is anybody able to confirm that I do indeed have a 3 ton/1.5 ton mismatch based on the model numbers I posted above?

    Thanks!
    Outdoor unit: Lennox HS22-411V-2P
    Approximately 41,000 btu = 3.41 tons


    Evap. Coil: Lennox C16-21-00-1
    Approximately 21,000 btu capacity = 1.75 tons

    Looks like a poor match to me, but your Lennox dealer can tell you more.

  12. #12
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,727
    depending on coil match hs22-411 is rated 33,000-38,000
    btus. coil depending on 1 1/2 or 2 ton unit is 19,000-
    22,000 btu. definately a bad mismatch. probably dehumdified like a bandit but very costly to run.

  13. #13

    Reply of model to tonage

    hs18- aprox 26K btu 2ton
    hs19-311 2.5 ton

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