Results 1 to 8 of 8
  1. #1
    Join Date
    Nov 2006
    Posts
    7
    We need to replace a failed condenser unit 10ACB48-5P.
    We want to reuse the 1997 CB29M-51-1P coil. 10 Seer / 4T.
    Changing this airhandler would be Hell, so we're desperate to leave it where it is.

    1, What new Lennox condensing unit model would be most compatible with the old coil?

    2. Or could we change the evaporator coil, but keep the air handler?

    3. If you know anyone else who has the technical smarts to help, could you help us contact them?

    Thanks for your help.

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,311
    guess this means you don't like the answers you got in your other thread.
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    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Sep 2006
    Location
    erwin nc
    Posts
    86
    lennox dealer in nc , i did not see anything compatible with the cb29m-51, although something may work, not sure of the ratings.

  4. #4
    Join Date
    Nov 2006
    Posts
    7
    On the contrary "BeenThere". We learned a lot on the other thread. I am so grateful to all that contributed their ideas.

    Some knowledgeable people said its OK, to attempt to put a new condensing unit on the old air handler. Now I'm just looking for the best match and therefor a better chance of sucess.

    The obvious best choice- A complete new system, isn't an option, due to the house and the cost.

    I am not an HVAC professional. I have gotten bids from several hvac contractors. Lets just say that if these guys were doctors, they problably wouldn't even check your blood pressure. So I got scared and came here looking for help.

    Thanks for watching over me. I'll send a followup in a month, so we all know the end result.

  5. #5
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Originally posted by rlj1117
    lennox dealer in nc , i did not see anything compatible with the cb29m-51, although something may work, not sure of the ratings.
    Plug in that air handler model number into the ARI search.
    The Lennox 13ACD-042, 048 and 060 are all current production lennox condensing units, and the Lennox 13HPD-042 and 048 are current production heat pumps that are ARI rated with the CB29M-51 air handler. The matchups get right around 12 SEER.

    The rating those units get with that older "10 SEER" air handler is right in line with the thing from Carrier that someone posted recently showing what the actual effects of mismatching new units with older indoor coils is. Basicly a new 13 SEER outdoor unit will run right around 12 SEER with an older "10 SEER" indoor coil that has a TXV, and will have a very small reduction in capacity, but good reliability.
    Installing a new 13 SEER outdoor unit with a "10 SEER" indoor coil with fixed metering results in greater reduction in SEER and capacity, and compressor life suffers.
    Installing a new 13 SEER outdoor unit with a pre 1992 cap tube coil for a <10 SEER system would be just stupid.


    I like the old Davenet better than the new one. For some reason I can't find most of the tech support and engineering handbook stuff I used to be able to find on the old davenet.

    [Edited by mark beiser on 11-25-2006 at 02:17 PM]
    If more government is the answer, then it's a really stupid question.

  6. #6
    Join Date
    Apr 2004
    Posts
    7,680
    Knowlegable people told you NOT to mismatch it. But you liked the answer your going with better.

    The air handers are almost always a pain to replace but dont be fooled into thinking it's going to last forever.

  7. #7
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Originally posted by docholiday
    Knowlegable people told you NOT to mismatch it. But you liked the answer your going with better.
    He can replace the outdoor unit with a current production Lennox unit without creating a mismatch.
    If more government is the answer, then it's a really stupid question.

  8. #8
    Join Date
    Nov 2006
    Posts
    7

    Smile Update- Happy Ending

    Lennox commercial support transferred me to a systems design engineer. He said the 10 SEER air handler is compatible with the 13 SEER condenser and will yielded 12 SEER in their testing. The engineer was very knowledgeable on the issue and also pleasant and helpful. Thanks Lennox, and my forum friends, the install cools well and we are hopeful that annual electric costs will reflect some savings. Thanks, G

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