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  1. #1
    Join Date
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    Setting EPR and TXV

    Hello,
    As customers are requesting higher evap temps I am trying to determine the BTUH of our MT display cases at those requested temps. i.e 20f, 22f, 24f etc. I have a Coriolus flow meter and all the software working well and have baseline information at a 20f evap. To simulate different rack temps I've installed a simple Sporlan ORIT, EPR valve. Raising the EPR presure from 20 to 22, psi converted, the Superheat changes and we have a cat and mouse game to get the system balanced again and SH always winds up high even when TXV is wide open.
    My question; What am I missing.

  2. #2
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    Re: Setting EPR and TXV

    What type of expansion valve are you using?

    How does the rest of the system look? Subcooling, liquid line sight glass, filters and strainers clean?

  3. #3
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    Re: Setting EPR and TXV

    Quote Originally Posted by seanf View Post
    What type of expansion valve are you using?

    How does the rest of the system look? Subcooling, liquid line sight glass, filters and strainers clean?
    Using a sporlan SBVE-AA TXV. which has worked for us for many years @20f evap temp. The condensing unit is one we pair with this case set-up all the time with TXV factory preset SH .
    Full charge, all components are new so filters and strainers are clean.

  4. #4
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    Re: Setting EPR and TXV

    Quote Originally Posted by kengineering View Post
    Using a sporlan SBVE-AA TXV. which has worked for us for many years @20f evap temp. The condensing unit is one we pair with this case set-up all the time with TXV factory preset SH .
    Full charge, all components are new so filters and strainers are clean.
    Is the sizing of the EPR ok?
    Do you have a sight glass you can use to check you have a constant solid liquid supply to the TXV?

  5. #5
    Join Date
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    Re: Setting EPR and TXV

    Are you calculating superheat on the evaporator pressure, upstream of EPR valve?
    Last edited by RANGER1; 23-05-2024 at 10:04 PM.

  6. #6
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    Re: Setting EPR and TXV

    SH calculated at the access port at the TXV sensing bulb.

  7. #7
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    Re: Setting EPR and TXV

    https://www.parker.com/content/dam/P...-090/90-20.pdf

    Do you have any flow through EPR when TX valve fully open & what is pressure upstream & downstream at that point.
    Instruction suggest 30 minutes settling period.
    Air on/off temperatures also gives good information on how it is working or not.
    You could treak pressure setting down a little to see if flow etc comes back as a test.

  8. #8
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    Re: Setting EPR and TXV

    Fitting an EPR will mess with TXV as you are putting a false restriction on the suction line, the EPR will open / close to maintain its setting irrespective of the TXV. I only come across EPR on rack type systems to allow higher suction pressures on display cases.
    Mostly found in the southern part of this green and pleasant land.

  9. #9
    Join Date
    Dec 2005
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    Re: Setting EPR and TXV

    Thanks for all the idea sharing. Seems we just needed to make very small adjustments and be patient. One of the difficulties I face is working from home and trusting that my guidence to the Lab Guys is understood and executed.

    Thanks again, Ken

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