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Thread: TXV Question

  1. #27
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    im pretty sure by looking at the design of the valve. the equalizer tube(suction pressure) puts pressure on spring which is driven by the bulb pressure. if the equalizer was blocked the valve would shut down.

    maybe someone else can chime in. im not at my computer.

  2. #28
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    ok found it.....this should clear it all up

    http://www.sporlanonline.com/10-37.pdf

  3. #29
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    THere is only one opening force on a TEV. That is the bulb which is pushing down on the needle. Warmer bulb, Valve throttles open.
    THe Closing force is evaporator pressure and spring pressure.

    In regards to the PDF Gravity posted I am pretty sure when they are talking about high superheat/ low suction being a blocked equalizer they are referring to the seal around the pushrods leaking. This gas cannot escape because of the blockage and pushes up on the diaphragm. This counteracts the opening force of the valve..
    Gotta have the right tool for the job!

    Where is all the stuff MADE IN THE USA?

    "Thats what we do Troy. Incredible, Invisible, Imbelivable things. We are an Unseen, Unknown, Unvincible fraternity of craftsman.."

  4. #30
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    Quote Originally Posted by millertime77 View Post
    Read most of the PDF, a good one indeed, and figured out that it is 2 oppossing forces that control the flow of refrigerant, the charge in the bulb against the back pressure leaving the evaporator. So I guess I was wrong in my thinking that pressures equalize in a txv system, they don't? They do though equalize in a system using a piston as a metering device?
    Yes many TEV's do equalize. However they do it in a manner differently then you first thought. Basically there is hole drilled in the valve body. They are different sizes and Sporlan stamps the size of the port next to "BP" on the side of the valve.
    York for example on residential systems do not have this so the pressures dont equalize.

    OF course on captubes or orifices the pressure does equalize.
    Gotta have the right tool for the job!

    Where is all the stuff MADE IN THE USA?

    "Thats what we do Troy. Incredible, Invisible, Imbelivable things. We are an Unseen, Unknown, Unvincible fraternity of craftsman.."

  5. #31
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    Should be fine. I've installed a few and the equalizer line had a schrader depressor. Zero issues with many a mile on them.

  6. #32
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    Quote Originally Posted by gravity View Post
    im pretty sure by looking at the design of the valve. the equalizer tube(suction pressure) puts pressure on spring which is driven by the bulb pressure. if the equalizer was blocked the valve would shut down.

    maybe someone else can chime in. im not at my computer.
    I understand what you are saying but how does a non bleed valve work? I though with the rising suction pressure forces valve closed. With lower suction pressure ie 0 and warm bulb shouldn't valve tend to open.

  7. #33
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    Also non bleed valves are a good thing as long as recip compressor has start component.

    Huge efficiency gains as well as increased dehum due to warm refrigerant not being able to warm up evap. Cycling losses

  8. #34
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    i found another pdf.

    it also shows high superheat/ low suction is a cause of a plugged external equalizer tube

    http://www.hintech-electric.com/cata...lp%20guide.pdf

    scroll to bottom for troubleshooting

  9. #35
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    Quote Originally Posted by gravity View Post
    i found another pdf.

    it also shows high superheat/ low suction is a cause of a plugged external equalizer tube

    http://www.hintech-electric.com/cata...lp%20guide.pdf

    scroll to bottom for troubleshooting
    Plugged to me is different than not connected. If plugged it would read higher than normal evap press.

    If the evap pressure force acts in the closing direction and it is non existing due to no schrader depress wouldn't you assume valve would stay wide open.

    That is a neat pdf and it will be kept. I appreciate it.

  10. #36
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    Quote Originally Posted by SBKold View Post
    I understand what you are saying but how does a non bleed valve work? I though with the rising suction pressure forces valve closed. With lower suction pressure ie 0 and warm bulb shouldn't valve tend to open.
    When the compressor shuts down the low side pressure will begin to rise, increasing the closing force. The valve closes.

  11. #37
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    if its plugged it would be the same as not connected

  12. #38
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    ive never witnessed a clogged or capped off tube. but going by the troubleshooting guide i linked it saids a plugged tube would have low suction and high superheat

  13. #39
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    What I believe happens is very small amount of pressure from the high side enters into chamber where it never enters the low side. Hence keeping higher than normal closing force.

    Now if the equalizer were never connected would be the only way to have wide open valve.

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