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  1. #53
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    Quote Originally Posted by Red Man View Post
    They're supposed to swing when you adjust the txv. If they didn't, that would be a sign of a txv problem. If you give it fifteen minutes or so it should level out. What kind of txv? I've found Alco valves to be much more difficult to adjust than Sporlan. They hunt worse and need more extreme adjustment.
    It is a sporlan txv. The model number is above. I know the txv should swing both the temps but it should also raise and lower the SH when you make that adjustment, correct me if i am wrong on this, but it is not. It just keeps swinging it. I do believe a high superheat and a high sub cooling at the same time is a sign of txv problems isn't it?

  2. #54
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    Jul 2012
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    Quote Originally Posted by Jonjordan25 View Post
    Yes the suction line temp is the saturation temp. I measured the evaporator discharge temp at a shrader valve located on the discharged line behind the evaporator. I measured the txv bulb temp on the txv bulb with a temp clamp. And lastly i do not know why it highlighted some of the quoted text from me in red. It did not show it in red when i typed it up.
    Lol, I highlighted them in red so you'd know what my questions were about.

    I'm still not exactly clear on the evaporator discharge temp. Are you saying that is a pressure converted to a saturation temp, or is it a measured temp? You said you measured txv bulb temp on the bulb? You should be measuring the pipe temp next to where the bulb is mounted, the pressure on the evap, and use that to calculate evap superheat.

    The txv bulb cannot be 26 degrees warmer than box temp if it's mounted correctly. Where would that heat be coming from?

  3. #55
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    Quote Originally Posted by Jonjordan25 View Post
    It is a sporlan txv. The model number is above. I know the txv should swing both the temps but it should also raise and lower the SH when you make that adjustment, correct me if i am wrong on this, but it is not. It just keeps swinging it. I do believe a high superheat and a high sub cooling at the same time is a sign of txv problems isn't it?
    Yes, high superheat and high subcooling is a sign of a bad txv or a liquid restriction. You have something else going on though if the txv bulb is 26 degrees warmer than box temp.

  4. #56
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    Jun 2017
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    Quote Originally Posted by Red Man View Post
    Lol, I highlighted them in red so you'd know what my questions were about.

    I'm still not exactly clear on the evaporator discharge temp. Are you saying that is a pressure converted to a saturation temp, or is it a measured temp? You said you measured txv bulb temp on the bulb? You should be measuring the pipe temp next to where the bulb is mounted, the pressure on the evap, and use that to calculate evap superheat.

    The txv bulb cannot be 26 degrees warmer than box temp if it's mounted correctly. Where would that heat be coming from?
    The evaporator pressure is 9.7psig. I measured it on the evaporator discharge line right where that line exits the evaporator box. There is a shrader valve there that i hooked my gauge on via the low side. The txv bulb is attached directly to the horizontal part of the discharge line right outside of the evaporator box. I connected a temp clamp right on the bulb and received a reading of 46f. Tomorrow i can attach it to the discharge line itself but the manufacturers manual said to take the reading from the bulb. I have read that you can test the bulb by putting out in warm water. If the superheat comes down then the bulb had lost some its charge.

  5. #57
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    Feb 2006
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    Phoenix,AZ
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    Quote Originally Posted by Jonjordan25 View Post
    It is a sporlan txv. The model number is above. I know the txv should swing both the temps but it should also raise and lower the SH when you make that adjustment, correct me if i am wrong on this, but it is not. It just keeps swinging it. I do believe a high superheat and a high sub cooling at the same time is a sign of txv problems isn't it?
    Pump the system down and pull the strainer out the TXV and clean it. If that doesn't work replace the TXV. Your suction pressure is too low for a 1 box. Your head is low too. Your system isn't doing all it's work!! Also, when you say evaporator discharge line? Do you really mean the suction line? Replace the dryer too while your at it.

  6. #58
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    Quote Originally Posted by Jonjordan25 View Post
    The evaporator pressure is 9.7psig. I measured it on the evaporator discharge line right where that line exits the evaporator box. There is a shrader valve there that i hooked my gauge on via the low side. The txv bulb is attached directly to the horizontal part of the discharge line right outside of the evaporator box. I connected a temp clamp right on the bulb and received a reading of 46f. Tomorrow i can attach it to the discharge line itself but the manufacturers manual said to take the reading from the bulb. I have read that you can test the bulb by putting out in warm water. If the superheat comes down then the bulb had lost some its charge.
    Take your K-12 probe,loosen the sensing bulb clamp,place the K-12 probe under the bulb on the pipe.
    Tighten down the sensing bulb clamps,wrap it with insulation. Then take your pressure to temp readings to find out your superheat at the outlet of the evaporator. If she hunts,that valve is not adjusted or too large for the evaporator. You will be able to read it when your suction temp drops the valve is opening,when it raises,the valve is closing.It's not unusual to see 20 degree swings on pull down,but as it hits design temp in the freezer and the valve throttles down it will have less and less swing.

    It's too bad no one cut in a tee on your 5/8 LL so you can determine a good column of LL pressure/temp on incoming.
    FEN

  7. #59
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    Dec 2014
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    Just a thought here on the high suction temperature leaving the evaporator is it possible that you have a suction liquid heat exchanger inside the evaporator?

    Sent from my SM-G930V using Tapatalk

  8. #60
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    Jun 2017
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    Quote Originally Posted by the mojo View Post
    Take your K-12 probe,loosen the sensing bulb clamp,place the K-12 probe under the bulb on the pipe.
    Tighten down the sensing bulb clamps,wrap it with insulation. Then take your pressure to temp readings to find out your superheat at the outlet of the evaporator. If she hunts,that valve is not adjusted or too large for the evaporator. You will be able to read it when your suction temp drops the valve is opening,when it raises,the valve is closing.It's not unusual to see 20 degree swings on pull down,but as it hits design temp in the freezer and the valve throttles down it will have less and less swing.

    It's too bad no one cut in a tee on your 5/8 LL so you can determine a good column of LL pressure/temp on incoming.
    The mojo, thank you for the tip. I habe been waiting for the box to pull all the way down but everyone it gets close, the suction line freezes and the compressor freezes and the system shuts down. Today i removed all the old insulation and put new insulation on. Also i did not stop at the outside unit, i ran the insulation all the way inside the unit to the compressor. I then started the unit and the box pulled down. I was finally able to adjust my SH at the compressor to 25 degrees. The manufacturer calls for 20 to 40 degrees. My sub cooling is still high but i am definitely taking a step in the right direction and the unit is running as we speak. Also using your type and placing a temp probe between the bulb and suction line gave me a completely different reading which was much lower. Thank you guys for your help through this learning process.

  9. #61
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    Dec 2014
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    Ice on a low temp compressor is fairly normal. Just means it's below 32f and there's moisture in the air.

    Sent from my SM-G930V using Tapatalk

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