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  1. #1
    Join Date
    Jun 2008
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    Question What are these lines? What should they be doing?

    Hey guys,
    I've lived in my house for 7 years and had several HVAC issues. About 3 years ago it was a clogged condensate line. The AC guy blew it out with compressed air and voila.

    Then last year the compressor refused to turn on and the AC guy said that some switch or relay needed to be replaced. He also replaced the old time capacitor with a newer one.

    Then tonight the HVAC was running, but started to blow less than cool air.

    I then realized that it had been a long time since I poured the bleach down the condensate line and did it immediately and flushed with a gallon of water so I could run outside and see if it was coming out. It was so everything is good there.

    Then I realized that I couldn't recall if the condensate line was capped at the first or second opening. I then also realized that I'm not sure what should be happening at each opening.

    So here's a photo to hopefully give you a view at my system.

    Currently, here is what I can tell you. The PVC opening closest in the photo has cool moist air blowing out of it when the cap is off and the HVAC is running.

    The PVC opening in the rear has nothing coming out of it when the HVAC is running and the cap is both on and off the closer PVC opening.

    So the questions are:
    1) How does this pvc piping system work?
    2) Should the cap be on when running? On which opening?
    3) Should air be coming out of the openings when running? Both openings?

    Is there anything else I should know about what should be happening when the system is operating properly? Or when there is a problem?

    Thanks a ton! or maybe my system is larger in which case it would be thanks 2-tons! (lame attempt at HVAC humor, but I had to try!)


  2. #2
    Join Date
    Aug 2004
    North Richland Hills, Texas
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    Plug the cap in the opening that air is blowing out.
    The opening that air is blowing out is a cleanout for the the trap in the drain line that is between the 2 openings.
    The trap is there to prevent air from being blown through the drain line.
    The opening after the trap, that air doesn't blow out of, is a vent for the drain, to keep it from becoming air locked.

  3. #3
    Join Date
    Oct 2006
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    1.Your sys should be service every year by pro
    2.Not blowing cold enough could be low on freon
    2.Not blowing as use to could be dirty filter or freezing coil do to low on freon
    3.Use white vinegar to pore into pump works better then beech
    4.First to left drain should have cap the one to right doesnt metter
    the idea is when drain is on negative side (which in ur case is on positive side)doesnt suck dirt or when sys i off bugs and i.t.n.
    5.air coming out thru left drain is normal if is very storng could be due to small supply duck (high static pressure)

  4. #4
    Join Date
    Jun 2008
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    Thread Starter
    Thanks guys. That was very helpful for me.


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