Replace AC unit

Discussion in 'HVAC Heating & Cooling' started by Atom, May 13, 2011.

  1. Atom

    Atom New Member

    Messages:
    16
    Location:
    Louisiana, USA
    My house has 15 yrs old. It has 2 Goodman AC units, 1 for up and 1 for down. The up unit (CK-30 1B) has bit the dust. I would like to replace it with a 3 ton unit and do as much of the work as possible myself. The evaporator coil was replaced about 5yrs ago. I'm thinking of a 13 SEER 3 ton Goodman as a replacement. I'm hoping the existing evaporator coil will work, but I'll have to check with the AC service that put it in. I'm confident the electrical wiring and breaker is adequate for the proposed service. What I'm hoping to do is have my AC service remove the refrigerant from the existing unit at which point, I would disconnect the old unit and set and reconnect the plumbing and electrical for the new unit, and then have them do the rest. I ask them some time ago what it would cost to replace the unit, and it is simply more than I can afford. Any advice on how to proceed would be appreciated.
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Your Ck-30 is 2½ ton. The 5 year old coil may well be 10 SEER. Even if it is 13, you can't get away with oversizing the outdoor unit. If the coil is 2½ ton, that is a problem. But it also is quite possible the coil is rated 2½/3. Your service tech should be able to determine if there is a proper ARI match on your new 3 ton unit to the existing coil.

    Do you have the equipment to bleed nitrogen while your are silverbrazing the new pipe connections? Very few contractors I know would touch the arrangement you are proposing. Would they be willing to put THEIR warranty on this system???

    Are you going to use a Dry 22 unit? or switch to 410??
  3. Atom

    Atom New Member

    Messages:
    16
    Location:
    Louisiana, USA
    Thanks jimbo. What are your thoughts on R22 vs 410? I know the 22 is being phased out, but there are evidently some issues with the 410, especially when converting an existing system. I've done some reading in the meantime, and I think what I might try to do is just buy the materials myself and let the contractor do the rest. Since I'm really trying to keep the cost down, it would probably be cheapest to just replace the existing condenser unit in kind and leave everything else alone?
  4. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    There aren't too many places who will sell you a condensing unit, especially a dry22. Buy a condenser on the internet, or some fly by nite outfit...WHO will give you warranty parts?
    Contractors make some of their living by making a profit on selling the equipment. SO take that away from him and what kind of work will you expect? You certainly wont expect him to come back and provide free labor on any warranty work.

    I sound like a wet blanket on your parade here, but it's a cold cruel world. Or in your area, it's a HOT cruel world, soon to be underwater!
  5. Atom

    Atom New Member

    Messages:
    16
    Location:
    Louisiana, USA
    I'm simply going to ask him if he will install it if I buy it. He can always say no. I have done most of my own home repairs my entire life and no doubt saved a bunch of money in the process. I do not owe a contractors, doctors, and lawyers a living. They are entitled to what they earn and I'm entitled to keep as much of what I have as I can. I'm sure in your mind I'm just another cheapskate homeowner, but there is more than a little you don't know. But, thanks for your help.
  6. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Atom... I did not mean to imply you are a "cheapskate homeowner". I am just as frugal as the next guy. I am paying $4.35 for regular these days! So the economy is not our friend right now! If you can find a competent contractor to work with you, I am all for it. But I do know a thing or two about the HVAC industry. I am in contact with people every day who have destroyed a brand new A/C unit because what worked in the "shade tree mechanic" days does not work now. Today, it is essential to bleed nitrogen, and many guys skip that, and wondor why the compressor burns out in 3 months. With dry units, you have to put in 5 pounds of R22 BEFORE you start the compressor. Guys think old-school, and start it up first. Compressor will seize up trying to pump dry. I have known guys to dump the five pounds quickly as possible, and slug the compressor with liquid. And you MUST charge to super-heat ( sub cool on a heat pump). A guy the other day had 70 psi low side and 235 hi. He figured that was good, and couldn't figure out why it wouldn't cool. When I got him to check his actual temps, he had 45º superheat. He was POSITIVE he had enough charge, but he was a good 5 oz short! So please, at least find a contractor with a solid reputation for knowing what he is doing.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,618
    Location:
    Cave Creek, Arizona
    If the AC guys in your area are like a lot of plumbers in this area, their LABOR charges for an install only INCLUDE a "fudge factor" to compensate for the loss of profit on the sale of the parts, (often equal to what they would have made but they avoid the liability for making service calls since it is not their responsibility to guarantee it).
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,995
    Location:
    New England
    FWIW, way back when, I was able to buy some equipment at employee prices...way below what the installer could. I did the emplacement and electrical hookup of the air handler and compressor unit, then paid a contractor to do a final check, install the refrigerant lines, pull vaccum, and set it up and check it out. The cost was in the order of $350, but this was a long time ago. SOme contractors I called wouldn't touch it, but the guy that did the work was a certified installer for that brand, and agreed to do the work. SO, you can find someone to do this, but you may not actually save a lot of money. The combination of me doing what I did, and access to employee prices, saved me about $1k at the time. Can't do that anymore, unfortuneately. Just hope what I have lasts a very long time!
  9. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,246
    Location:
    Land of Cheese
    If you could find a willing contractor, I would recommend that you set the new condenser unit and wire it up, but leave the copper and refrigerant work to the contractor.
    As others gave said, if anything goes wrong during charging or down the road, you cannot expect the contractor to provide any type of support.
  10. Atom

    Atom New Member

    Messages:
    16
    Location:
    Louisiana, USA
    Well, I went out and got a window unit this morning which will at least allow me to be in my office until I can figure out what to do. I did have a phone call with the my AC repair service (they were just here the other day and charged me about $300 to put in a start kit for the compressor and add freon. Unfortunately, this repair did not last long, but that can't be helped. I was going to try to limp through one more summer with the existing unit, but it didn't make it.) He thought it would be about $500 to just install the condenser unit, but I'll have to talk to the boss on Monday.

    cacher_chick, I was going to do what you suggested, but I want to set the new unit right where the old one is, and they would have to come and remove the refrigerant anyway, and since it's probably just a half day job for them, I think any savings due to my labor would be lost if they have to make two trips.

    Thanks to all for the suggestions and recommendations.

    atom
  11. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,125
    Location:
    Houston, TX
    Freon or R22 ?

    Atom, Did they check for leaks or just put more refrigerant in ?

    The Goodman should have lasted longer that it did.

    Most common problem is the Cap for the Compressor.

    A lot of servicemen Overcharge the units, and burn the compressor up.
    If they did not check or repair the leak and just charged it, They Screwed You.

    I would find someone else , that knows what they are doing.

    Good Luck.

    DonL
    Last edited: May 14, 2011
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,995
    Location:
    New England
    IN some places, I've heard it's illegal to just add refrigerant without checking for leaks first. This is a good idea anywhere. While the newer stuff is less damaging than the old, it all is nasty and can't legally be vented to the atmosphere intentionally.
  13. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,125
    Location:
    Houston, TX
    Yes Jim , a lot of them don't follow the rules.

    They may have put 410 in a 22 system, I would not be surprised.

    DonL
  14. Atom

    Atom New Member

    Messages:
    16
    Location:
    Louisiana, USA
    They have been working for me a long time, so I trust them, but it did occur to me that they screwed up. The lead person on the call was someone who has been here many times, but he did have a kid with him who I'd never seen before. Only way I'll find out is if they tell me. This is one of the good things about DIY. If there is a mistake you definitely know who made it.
  15. Atom

    Atom New Member

    Messages:
    16
    Location:
    Louisiana, USA
    It happens that my fears of a totally dead condenser were unfounded. They came back today and replaced the starting capacitor on the compressor and it's now running again. Thanks again to everyone for your help.
  16. Atom

    Atom New Member

    Messages:
    16
    Location:
    Louisiana, USA
    Back to square one. Today my AC guy came and pronounced the compressor dead, so I've ordered a new 3 ton condenser and evaporator coil (Goodman R-410A). He said he would come and start it up once I've got it installed. I've already demo'ed the old stuff. Re-installation seems reasonably straight forward. I have ordered some of the solderless bonding agent, but I will probably do some testing first to see how well it works. Anyone have any experience with it? I've done a lot of different things, but this will be a first.
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