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  1. #1

    Confused about estimates

    I am a homeowner in Birmingham, AL needing to replace an old, 3 ton Goodman central air conditioning unit. I have a 10 year old, 2 stage Carrier gas furnace that was top of the line at the time, and by all accounts is still in good condition. We do not use central alot because we have lots of trees around the house giving shade--but there are days that we definitely need it.

    We got estimate from an authorized Carrier dealer for 3 ton Carrier Comfort 13 SEER as well as a Performance 13 SEER, both with Puron. They include a cooling coil CNPHP4221ACA in their price for both units. In both cases, the estimate on these two units is the lowest I have received.

    I got another estimate from a dealer for Amana and Comfortmaker 3 ton with R410A that was considerably more.

    I got a third estimate from a authorized Lennox dealer (also selling Tranes) who took measurements one day and gave me the estimate the next. He gave me a quote for something that I really did not ask for, but may be a wise choice, all the same: the quote was for a Lennox XP13 heat pump (13 SEER) and a Trane TWR036 heat pump (14 SEER). He told me that it would be advantageous to go with the heat pump because it would provide heat when the temperature was 40 degrees or over outside, and do it more efficiently than the gas furnace. It is true that many of our fall, early winter and early spring nights would be 40+ degrees. Also, he included in the price a new "line set." He indicated that this was needed since we were going to another type of refrigerant. The Carrier quote does not include a new line set. The Lennox and Trane estimate was higher than both of the two previous estimates

    Can anyone give suggestions on this? Do we need a new lineset? Is a heat pump really in order?

    Thanks

  2. #2
    Join Date
    May 2007
    Location
    Pittsburgh
    Posts
    43
    FWIW, I am in the 'get an estimate' phase too, looking for a new furnace/AC, and so far I have received two estiamtes. The first estimate listed pricing and brand name for three furnace/AC units, but there were no model numbers or stage information. The second estimate was more detailed, listing four furnace/AC units with stage and model numbers, but it also had other buyable options like programmable thermostat, heat pump, air cleaning, humidifier, mold control, and attic fan. Both estimates were for connecting the new unit to the current duct system but neither addressed whether the current duct system is adequate. I have a couple more estimates next week, from companies that do load calculations, something I learned should be done by reading this site.

    That said, I know R22 is going to be phrased out, to be replaced by R410, so that could be why the need for a new line set, though I think you can still buy R22 AC units. The pros here can tell you more on that. All in all, I wouldn't hire a company based on lowest price. As the homeowner, you need to decide what you want and then really take the time to find a company that will help you make sure you are getting the correctly sized equipment for your house. This includes line size. I've read it over and over: It's not so much the brand of equipment as it is the skill of the installation. If you are happy with your current heating and monthly utility bill, and only want a new AC, then you might consider buying just the AC, though of course, it's really up to you.

  3. #3
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,887
    Dual fuel is becoming very popular in mild climates as the price of natural gas went through the roof. We're in a colder area than you but encourage our prospects to consider it. In our area, savings could be $200+ a winter over strictly gas heat. At that rate, payback is fast on the extra for a heat pump over A/C. Ask him for a Vision Pro IAQ control - it's a thermostat that interfaces a gas furnace and heat pump plus offers true staging for your 2 stage gas furnace.

    If a lineset is accessible to change, we want to even staying R22. Even more important changing refrigerants though not required. Just wise.

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,705
    Hard to go wrong with a duel fuel system.
    If electric gets too expensive later, you can use just the furnace for heating.
    Contractor locator map

    How-to-apply-for-Professional

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

  5. #5
    Join Date
    Dec 2006
    Location
    New Jersey
    Posts
    747
    Your line set does not need to be changed unless your new unit requires bigger suction lines. I use rx11 flush to clean out line sets when changing a r-22 system to a 410 system.

  6. #6
    Join Date
    Mar 2007
    Location
    Birmingham, AL
    Posts
    108
    I would certainly recommend changing the lineset if changing from R22 to R410A. While you can flush it, why chance it? If the lineset can be changed, change it.

    Dual fuel in Alabama is very common. A side benefit, if anything ever happens to the heat pump, you have gas backup heat until you can get the HP serviced.

  7. #7
    Join Date
    Dec 2006
    Location
    New Jersey
    Posts
    747
    so ishot do you change out a lineset in a burnout or flush it?

  8. #8
    Join Date
    Apr 2007
    Posts
    6,285
    Quote Originally Posted by acmech13 View Post
    Your line set does not need to be changed unless your new unit requires bigger suction lines. I use rx11 flush to clean out line sets when changing a r-22 system to a 410 system.

    R-11 usage:

    The solvent bottles are painted with extravagant claims many of which categorically are untrue.
    ………….leaves no residue
    Physically, these solvents have a substantially higher boiling point than R-11, and we could not get the solvent to phase into a gaseous state under high vacuum. Another negative is the oily texture of the solvent which imparted a thin film coating to all our glassware. It was clear-cut that large quantities of solvent would remain in any system so treated.
    .…. ……Neutralizes acid
    We investigated the general chemistry of the solvents. The solvents all had an acid number. Not a good sign, but not an unexpected result, since solvents which best dissolve oil must have an acidic ionic character.
    ……….non hydroscopic
    A readily identified compound in the solvent base uncovered Acetone. You can’t find too many compounds more hydroscopic than Acetone. Water adsorption from short term exposure to the atmosphere is faster and greater with Acetone than with a POE or PAG lubricant.
    ……….will not contaminate oil
    Now here is a direct contradiction to the top claim. If the product does not leave a residue why would there be concern for oil contamination. It is because the solvents are polar and will integrate completely with oil. The viscosity of Oil summarily degrades with solvent contamination.


    http://www.refrig.com/talk.html

    Written by:
    "Roger D. Holder, CM, BSME, is a member of the Southern San Joaquin Chapter in Bakersfield, Calif. He also is a refrigeration and air conditioning specialist at National Technical Transfer Inc., Englewood, CO 80155"

  9. #9
    Join Date
    Dec 2006
    Location
    New Jersey
    Posts
    747
    bigjon thats why after the flush we blow the lines out with nitrogen the suction line first then the liquid line.

  10. #10
    Join Date
    Apr 2007
    Posts
    6,285
    Quote Originally Posted by acmech13 View Post
    bigjon thats why after the flush we blow the lines out with nitrogen the suction line first then the liquid line.
    You didn't read the article did you?

    "I once sent out a new Service Tech to purge, evacuate and prepare a rebuilt compressor for start up on an old 25 ton system. This Tech was a rising star in the company having graduated with high honors from a top Refrigeration Trade School. He loaded the system up with about 10-15 lbs of R-11 backed with a bottle of nitrogen. After a few hours, the Tech called into the office complaining that his vacuum pump was not pulling down very well. I went out to the job site to assist. I arrived with the notion of a leak somewhere in the new connections. After the Tech explained to me everything he had done, I knew we were in for a long night."

    "Loading the system with R-11 turned into a nightmare. The solvent became trapped at low points in the piping. Every bend, nook and cavity in the piping contain small amounts of liquid R-11. Attempts to blow out the R-11 with nitrogen did not work. We connected two vacuum pumps and let'em run overnight. The residual R-11 was difficult, if not impossible, to completely boil off."

    "
    Recently, a few Chemical distributors have introduced [new] flushing solvents to internally clean piping. I bracket the word "new" here to bare out a half truth. These solvents have actually been around since the last supper. The only thing "new" is the intended application, "your next compressor burnout"."



    I would just leave at replace the lines...Unless you want to vac test them in between the new install to make sure you get your 50 micron reading (or as close as physically possible but def. under 250) If that's what they were quoted then I would leave it up to the contractor that est. that job IMO.

  11. #11
    If I was down there, I'd dump the gas furnace and use a higher seer split system heat pump with an adequate amount of supplemental electric heat in the fan coil and a programmable lockout control to prevent unnecessary electric heat staging on.
    And yes, if a new lineset is an option, I'd want that too.

  12. #12
    Join Date
    Jul 2003
    Location
    Central New Jersey
    Posts
    108

    dual fuel systems

    I would definitely consider either the Trane or the Lennox heat pump systems. Both manufacturers produce quality equiptment and comparable warranties and performance. Take good care
    Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world... AE

  13. #13
    Join Date
    Dec 2006
    Location
    New Jersey
    Posts
    747
    The first time i didn't click on that link. Im lucky i never experienced that problem. When converting thou we are only flushing the line sets. suction line first then the liquid line. Im happy with a 400 micron vacuum. this is what we use
    http://www.nucalgon.com/nucalgon/nuc...1?OpenDocument

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