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  1. #1
    Join Date
    Jul 2006
    Posts
    19
    3ton Reem, 12seer,5 years old-Checking the charge with the wheeler chart. High side is steady 200 and all temps look about in right but the low side pressure will gradully rise about 10pds then drop back. About 60 to 70 then quickly drop. The a-coil is in the attic and I haven't checked it yet. Any ideas what is causing this?
    Thanks
    Gary

  2. #2
    Join Date
    Mar 2004
    Location
    SE Michigan
    Posts
    17,894
    Size of line set and length? TXV or piston?
    " Kill a Commie for Mommy! "

    - Colonel David Hackworth (1930-2005), Korean War Vet

  3. #3
    Join Date
    Jul 2006
    Posts
    19
    Its a scroll compressor, lines match the system (3/4 and 3/8)-I think. Its a pretty long run, other end of a garage up to second story attic. Maybe 50 feet. The deltaT is about 14.

  4. #4
    Join Date
    Jul 2006
    Posts
    19
    Sorry, your talking about the mettering device on the a-coil? Not sure. I didn't think the newer ones used piston.

  5. #5
    Join Date
    Apr 2004
    Posts
    7,680
    could be the TEV hunting in lower load conditions or the bulb is not tight to the suction line like it should be.

    Also, odds are the LL should be 5/16 and "matching the unit" might mean a 25' vertical seperation is a little much for a heat pump. That's neither here nor there though.

  6. #6
    Join Date
    Jul 2006
    Posts
    19
    I looked up a TXV. I think I have seen something like this loose in the attic like the guy that installed it cut it out and pitched it aside when during the install. Read a little about hunting just now. Is this what I am seeing? Is it bad? I mean is this the reason my deltaT is lower that it should be?
    Thanks for the responce.

  7. #7
    Join Date
    Apr 2004
    Posts
    7,680
    hunting means the valve is bigger than the load. It's sort of another way of saying "overcorrecting". Thats not a valve problem, it's a load issue.

  8. #8
    Join Date
    Jul 2006
    Posts
    19
    Sorry, Don't understand. (load issue). Too much load. This is the upstairs of a two story house in Texas. Unit runs all the time just keep it below on 84 on hot days. -Newer house/good insulation not many windows. What are you suggesting for a solution.
    Thanks

  9. #9
    Join Date
    Apr 2004
    Posts
    7,680
    you might want to call a good techncian.

    Sorry rules prevent me from offering a technical solution and frankly with limited information, there wouldnt be much use.

    Is there a TXV or is there not a TXV?

  10. #10
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,046
    Don't use Wheeler chart on high SEER TXV systems, they are for less than 10 SEER with fixed orifice. Every Rheem I have seen has specific chart pasted on the service door. Use it ONLY.

    I am ASS U MEing TXV because a matched Rheem system above 10 SEER would be TXV. If mismatched coil, good luck!

  11. #11
    Join Date
    Jul 2006
    Posts
    19
    There is not one. It is laying in the attic. For somereason they didn't use it.

  12. #12
    Join Date
    Jul 2006
    Location
    NJ
    Posts
    356
    You may have noncondensables in the system or the wrong size txv. If no txv recover and clean refrigerant system, install correct txv. insulate the liquid line in the attic, dont laugh it's the correct way.

  13. #13
    Join Date
    Jul 2006
    Posts
    19
    I wish I could figure out how to attach a picture. The TXV is on the floor. The small coper line soldered into the cold line is cut and The high side goes straight into coil. I can hear gurguling noise in the lines. Could they of had trouble with the long run and replaced the TXV with a piston and probably didn't suck it back down right after they opened it up to remove the TXV? Think I should find a company to recover the freon, replace the TXV, and suck it down good. (Is that what you ment by cleaning). Is it going to be a problem being such a long run and the coil being probably 20 foot higher (2nd story attic) than the compressor?
    Thanks

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