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Thread: Setting EPR and TXV
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23-05-2024, 01:11 PM #1
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 20°f, 22°f, 24°f etc. I have a Coriolus flow meter and all the software working well and have baseline information at a 20°f 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.
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23-05-2024, 06:46 PM #2
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?Interested to keep learning. linkedin.com/company/refrigeration-itmc
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23-05-2024, 10:01 PM #3
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.
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02-06-2024, 03:06 PM #4
Re: Setting EPR and TXV
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02-06-2024, 03:08 PM #5
Re: Setting EPR and TXV
SH calculated at the access port at the TXV sensing bulb.
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02-06-2024, 08:41 PM #6
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02-06-2024, 10:20 PM #7
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.
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03-06-2024, 09:01 PM #8
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.
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08-06-2024, 01:54 PM #9
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