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Thread: TXV Question

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  1. #1

    TXV Question

    Just curious on the newer style TXV"s and coils. If you use the internal port on the inside coil to connect the braze-less TXV, do you remove the schrader or can you leave it in? I ask this because I've always brazed the included extensions and they never came with schraders installed. Logically the internal sensor block would keep it depressed and take readings just fine, but we all know manufactures never seem to build equipment well thinking logically; lol.!

  2. #2
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    are you talking about an external equalizer line? if it has a shraider depressor in it then you can leave the shraider in. i always take them out.

  3. #3
    No, on the newer internal coils they have a port inside the case, I hear it's used for the factory to pressurize them with nitrogen. I've always purchased the braze style TXV, for residential heat-pump/fossil furnace setups 13seer and over. I got a newer screw on style TXV today and I left the schrader in, now I'm nervous it may cause issues with the TXV later on. It cycled fine and pressures were good. It was to cold outside to trim the superheat and get good head pressure readings. I've never had to adjust any factory matched set before so I let them used the system until I can come back on a warmer day. Now I'm slightly worried about the TXV, and I really don't want to pump it down again.

  4. #4
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    a indoor evaporator coil? well if it doesn;t have a shraider depressor in it then you will starve your evaporator coil. you will have really high superheat.

  5. #5
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    Should be fine,,,,,,,,no worries.

  6. #6
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    ok, so you are saying the valves I am dealing with are internally equalized? If so what does the bleed port do?

  7. #7
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    I dont know what kind of valve your working on. Is there a 1/4" tube you braze into the suction line? IF so the Valve is externally equalized.
    The bleed port is a hole in the valve that allows refrigerant to bypass the valve in the off cycle.
    Did you start reading on Sporlan's site yet? Bulletin 10-9 and 10-10 will answer your questions. Take the time to read and understand them. If you need help ask the question. We will help.
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  8. #8
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    The valve that I am talking about replaced a valve that had a very small tube brazed into the suction line, that I thought was the external equalizer, and was replaced with a valve that had the same tube with a female flare and came with a 90 degree short piece of suction tube with the male threaded flare connection for, what I thought was the new equalization tube.

  9. #9
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    Quote Originally Posted by millertime77 View Post
    The valve that I am talking about replaced a valve that had a very small tube brazed into the suction line, that I thought was the external equalizer, and was replaced with a valve that had the same tube with a female flare and came with a 90 degree short piece of suction tube with the male threaded flare connection for, what I thought was the new equalization tube.
    That is the external eq line. But it doesn't dump refrigerant from the high side to the low side during the off cycle. A bleed valve does that instead. Did you read the PDF?

  10. #10
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    Quote Originally Posted by millertime77 View Post
    ok, so you are saying the valves I am dealing with are internally equalized? If so what does the bleed port do?
    internal eq. valves are found on small evaps such as reach-in coolers with little pressure drop!!! Here's a pdf from parker thats a little better than the one i posted earlier. http://www.parker.com/literature/Aft...V%20Theory.pdf

  11. #11
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    Oct 2010
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    Anderson, South Carolina, United States
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    I've never seen one with a valve core depressor on it so I always take the valve stem out. All the York's don't have a stem in it it comes with the outdoor unit packaged with the piston

  12. #12
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    Jun 2011
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    Detroit vicinity, Michigan
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    Yeah, if you don't pull the schrader........you're gonna have a bad time!

  13. #13
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    Aug 2001
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    I think he is referring to a situation such as a goodman Evap. When you install the external txv and they send you stubs, he is referring to using the Schrader factory installed on the suction line of the unit. The flare connection has a depressor on the end.
    ...

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