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  1. #1

    13 SEER condensing unit and 10 SEER coil?

    I am a general contractor. Recently an HVAC sub was called to replace a condensing unit (1.5 ton) in one of our small homes. He replaced the condensing unit which was a 10 SEER originally with a 13 SEER condensing. I asked if he needed to replace the old "A" coil also, and he said he thought it would work.

    When he charged the system, he could not get over about 60. It was just barely cooling. He informed me that it would "probably" need the 13 SEER coil.

    I think that he should have known better. He also wants to charge me for 10 pounds of R22.

    This feels very upside down to me. First, it seems that he should have replaced the coil before he tried to make it work. Second, with the condensing unit being new, it should have had a freon charge also.

    I know that you guys are mostly HVAC pros, but I would appreciate some help, here.

    I know carpentry, wiring, plumbing --- but not a lot about HVAC. I questioned him before the installation and asked if he should be putting in a different coil, so should I pay him for the 1- pounds of freon that is probably wasted since he will need to replace the coil, now?

    And isn't 10 pounds of freon a lot for a 1.5 ton system? BTW the line set is about 10 feet.

    Thanks,
    Bill

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
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    34,060
    Yes, 10 # in a 1.5 ton is nuts. What a maroon! Actually the mismatch should function, just not be efficient, reliable or full capacity. Wonder what else he screwed up?

  3. #3
    Join Date
    Sep 2008
    Location
    Phoenix AZ
    Posts
    219
    Probably overcharged the system, the mismatch does work but not recomended, 10 lbs for a 1.5 Ton its too much, even pump down will make the compressor scream in pain. if the indoor coil is plug up and not cleaned overcharging is common suction pressure will be low . yahoos and hackers do not know this so they add and add and then hooohhh sh%^^%T its not cooling properly.
    Last edited by Baja500; 06-27-2009 at 12:41 PM. Reason: correction

  4. #4
    Join Date
    Feb 2004
    Location
    Connecticut
    Posts
    1,666
    I have always been told that as long as you install a TXV on the 10 SEER coil it will work. I have not done it myself, but other guys in our company have, and said it works fine.

    I'll bet he did not install a TXV at the 10 SEER coil. And as for the 10 pounds of refrigerant.......it sounds like he just kept adding juice hoping that the suction pressure would come up. If you've got 10 extra pounds in that system, with only a 10 foot line set, DO NOT run that system until it is properly reapaired or you will ruin the compressor in a very short time.

  5. #5
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,321
    With only 10' of copper the system was overcharged to begin with the unit most likely had enough refrigerant for 15' to 25'.

    Call another company have then look at the coil and advise how to proceed.

    The ultimate answer is change the coil, next best install a TXV or at least verify the proper piston.

    Oh first get another contractor the one you have appears clueless at best.

  6. #6
    Join Date
    Sep 2007
    Location
    NC Coast
    Posts
    2,604
    WOW......... 10 pounds extra??? Heck... I know of 5 ton systems that dont take that much extra on a 3 story house! You can bet he has that indoor coil flooded and therefore flooding the compressor. If the compressor is sweating its A$$ off... then you KNOW its flooding... and it will eventually kill the compressor!
    Only way 13 seer condenser works on a 10 seer coil is if the indoor coil is large enough to handle 13 seer. most of the times its when the coil is able to be used on 2 different size condensers. example... a goodman 3036 or 1824.... can be used on a 2.5 and 3 or a 1.5 and 2 ton system. but airflow needs to be right!
    Silent Service........ Death From Below!

    Somewhere in Kansas, a town found a village idiot!

  7. #7
    Join Date
    Sep 2007
    Location
    NC Coast
    Posts
    2,604
    Quote Originally Posted by ct_hvac_tech View Post
    I have always been told that as long as you install a TXV on the 10 SEER coil it will work.
    Only if the coil is big enough
    Silent Service........ Death From Below!

    Somewhere in Kansas, a town found a village idiot!

  8. #8
    Join Date
    Jun 2004
    Location
    Location:Raleigh NC
    Posts
    9,613
    10# just for fun look on the Name plate and tell use what the Manfac. say?

    Maeybe the Hacks going for a lb/ft of lineset
    If you help others then you are a Success

  9. #9
    Thanks All! I'm going to tell this guy to take a hike, and he can forget charging me for 10 pounds of freon.

  10. #10
    Join Date
    Jun 2004
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    Location:Raleigh NC
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    9,613
    Bill let us no what the Name plate says the Weight is
    If you help others then you are a Success

  11. #11
    Join Date
    Feb 2004
    Location
    SC
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    20,677
    Yup. Should'a been new condenser, new coil, R410, and an R11 lineset flush if mfr. says it's okay. Otherwise, new lineset, too.
    No reserve. No retreat. No regrets.

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  12. #12
    Join Date
    May 2002
    Location
    Houston Texas
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    Quote Originally Posted by Bubbleheadski View Post
    WOW......... 10 pounds extra??? Heck... I know of 5 ton systems that dont take that much extra on a 3 story house! You can bet he has that indoor coil flooded and therefore flooding the compressor. If the compressor is sweating its A$$ off... then you KNOW its flooding... and it will eventually kill the compressor!
    Only way 13 seer condenser works on a 10 seer coil is if the indoor coil is large enough to handle 13 seer. most of the times its when the coil is able to be used on 2 different size condensers. example... a goodman 3036 or 1824.... can be used on a 2.5 and 3 or a 1.5 and 2 ton system. but airflow needs to be right!
    Almost any condenser will work on any coil it will change how the condenser works, it will change the SHR but it will work. A compressor is a pump it does not care what it is pumping to, you just have to adjust the charge.

    Will a 13 SEER condenser work on an older coil (coils DO NOT have SEER ratings) yes it will, the results will not produce a 13 SEER match it may produce 12.6 or 6.2. The longevity of the compressor will be determined by many factors least of which is the physical size or dimensions of the coil.

  13. #13
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,321
    Quote Originally Posted by bootlen View Post
    Yup. Should'a been new condenser, new coil, R410, and an R11 lineset flush if mfr. says it's okay. Otherwise, new lineset, too.
    Hey boots consider that being 12 years old yes it should get a coil but many manufacturers use the same coil today that they used then, Carrier does or did until they brought on the newest coil. In fact the CE3AX coil was used for more than 15-years and Carrier says it is fine with a TXV on most units up to 15 SEER. We had 13 SEER even 16 SEER units back then.

    Since we do not know what size coil or A/H might be installed an assumption is being made that the coil is 1.5-ton. First how many 1-5-ton coils have you ever seen, it is more than likely a 2-ton coil even possible that it was a 3-ton.

    Is anyone here ready to say a 2-ton coil or a 3-ton coil from 12-years ago will not produce a 13 SEER match on a 13 SEER 1.5-ton condenser.

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