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Thread: TXV Question

  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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    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

  7. #7
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    Yeah, if you don't pull the schrader........you're gonna have a bad time!

  8. #8
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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.
    ...

  9. #9
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    The case coils that trane sends us, has a Schrader core in it. if you attach the equalizer tube to the port and leave the Schrader core in it WILL mess with the operation of the valve. if you observe the fitting of that equalizer tube it has no mechanism to depress that Schrader core. I have fallin victim to its ways from time to time.. what i am saying is that you have to remove it if there is a trane TXV in place.

  10. #10
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    I wouldnt leave a valve core in for something like that because anytime it would need to be taken off the system will be empty of gas anyways. If not and for some reason the system is slow to equalize, you will wind up with compressor starting issues if the cycles are close together, sometimes even when they arent. Not as much if you have start componants but why go thru the hassle. Take out the core.
    l8r

  11. #11
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    The external equalizers purpose is to, obviously, equalize pressure, so the compressor doesnt need a lot of amperage during start-up. If you have a valve core in the equalizer connection to the suction line this process will slow down and you will end up installing a hard start kit. Every expansion valve I have ever installed comes with a male threaded flare fitting on the 90 degree suction tube portion with no shrader in it, and no depreesor on the female flare fitting on the equalizer tube from the valve. The shrader should be removed if your valve has one.

  12. #12
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    Quote Originally Posted by millertime77 View Post
    The external equalizers purpose is to, obviously, equalize pressure, so the compressor doesnt need a lot of amperage during start-up.
    http://www.emersonclimate.com/Docume...re-article.pdf

  13. #13
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    Quote Originally Posted by millertime77 View Post
    The external equalizers purpose is to, obviously, equalize pressure, so the compressor doesnt need a lot of amperage during start-up. If you have a valve core in the equalizer connection to the suction line this process will slow down and you will end up installing a hard start kit. Every expansion valve I have ever installed comes with a male threaded flare fitting on the 90 degree suction tube portion with no shrader in it, and no depreesor on the female flare fitting on the equalizer tube from the valve. The shrader should be removed if your valve has one.
    That is incorrect. You should read up on the operation of the TEV...
    Sporlans website has a lot of good info. THey changed it, Im having a hard time posting the link.
    Last edited by Pascone10; 09-08-2012 at 12:04 PM.
    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.."

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