Page 2 of 2 FirstFirst 12
Results 14 to 19 of 19
  1. #14
    Join Date
    Feb 2005
    Posts
    25
    BOth increace and yes it should not Hunt but he asked the question Reduce airflow. ALso a block in the equilization tube, Sensing liquid on the bulb, Bad location of the bulb,low sub cooling, Ect. all can cause Hunting situation

  2. #15
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,903
    Originally posted by wendel
    Thanks for the explanation, Shophound. I think you corroborated the HVAC company's position. If the evaporator is oversized, the superheat will, most of the time, be greater than 10 degrees and will be full open giving a full flow of R-22. Therefore the TXV would be open and the flow limiting device would be the TXV's orifice.
    Define over sized.

    Many high seer units use an indoor coil rated at a higher btu then the outdoor unit. And the txv will still maintain proper sh.

    What is your hvac company telling you?
    Contractor locator map

    How-to-apply-for-Professional

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

  3. #16
    Join Date
    Jun 2004
    Posts
    247
    Thanks for the reply, beenthere. The company is telling me that because the evaporator is 4 tons and the condenser is and TXV are only 3 tons that the coil load will be such that the TXV will be wide open 90% of the time and therefore be acting like a piston with one constant flow 90% of the time.

  4. #17
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,903
    When the system first starts the valve may be fully open, but as the coil gets colder it will throttle down.
    The lower the humidity in your house the more it will close down also.

    We install York/Luxaire, and they use 4 ton indoor coils on their 3 ton 15 seer units, and the txv's throttle down as the latent heat is removed, and I believe most manufactures do just about the same as far as the indoor coil being 1/2 to 1 ton larger then the outdoor unit.

    Your contractor may need to send their guys to more classes.
    Contractor locator map

    How-to-apply-for-Professional

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

  5. #18
    Join Date
    Dec 2002
    Posts
    9,871

    I have seen too many

    Good compressors die an early death from using a piston instead of a txv. Too many techs shy away from txv's because they simply don't understand them.

  6. #19
    Join Date
    Dec 2002
    Location
    in a house, Appomattox, Va.
    Posts
    3,292
    We sell Gibson, too, and if I recall correctly all their units have pistons (even 15seer), 60a breakers in all a/hs regardless of wattage, 3/8" liquid lines for all condensors, same defrost board for all ht pumps.
    I figure they're trying to stupid proof the units as well as simplify inventory control.
    Col 3:23


    questions asked, answers received, ignorance abated

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event