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  1. #1
    Join Date
    May 2019
    Location
    Albuquerque NM
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    Environmental Chamber

    i have an ESPEC water cooled walk in chamber with 404A and 508B refrigerants. The system appears to have a leak in the 508B circuit due to ice build up on compressor it is also extremely slow to reach set point static pressure is slightly lower than the nameplate (unit is in Albuquerque NM 5000 ft above sea level). I have leak checked the system when it is off and when it is running and after it has stopped and found nothing. I have even injected dye into the system and can find no leak anywhere. It's starting to look like there may be another issue with this unit maybe a problem with the 404 circuit? Any suggestions

  2. #2
    Join Date
    Aug 2015
    Location
    Buffalo,NY
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    821
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    Environmental Chamber

    Are you sure the high side isint leaking into the water coil?


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  3. #3
    Join Date
    May 2019
    Location
    Albuquerque NM
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    Thread Starter
    That had occurred to me I did open up the water loop and swept it with an electronic leak detector and not even a chirp. Any test on the desuperheater or the condenser would require major modifications and down time i want to eliminate as many of the less challenging possibilities as I can before going down that road. It does make sense that the condenser could be the culprit but i see no bubbles in the sight glass I don't have the temps and pressures in front of me but they seemed alright as I recall. Maybe an issue with the 404 expansion valve into the cascade condenser?

  4. #4
    Join Date
    Mar 2008
    Location
    kansas
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    1,198
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    Make sure your high stage is operating properly before trying to diagnose the low stage. What temps are you running ? What is the reason for the call?
    Honeywell you can buy better but you cant pay more

    I told my wife when i die to sell my fishing stuff for what its worth not what i told her i paid for it

  5. Likes Metalman0880 liked this post
  6. #5
    Join Date
    Aug 2015
    Location
    Buffalo,NY
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    Quote Originally Posted by Groghouse View Post
    That had occurred to me I did open up the water loop and swept it with an electronic leak detector and not even a chirp. Any test on the desuperheater or the condenser would require major modifications and down time i want to eliminate as many of the less challenging possibilities as I can before going down that road. It does make sense that the condenser could be the culprit but i see no bubbles in the sight glass I don't have the temps and pressures in front of me but they seemed alright as I recall. Maybe an issue with the 404 expansion valve into the cascade condenser?
    I guess at this point if it were me from what you just said, I would probably start at square one. Verify everything mechanical is working correctly. If you’ve got dye in the system and have going over everything, now you say the sight glass shows good I would be leaning towards something else. With no real running info it makes it hard to say.


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  7. #6
    Join Date
    May 2019
    Location
    Albuquerque NM
    Posts
    6
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    Thread Starter
    They are running the chamber down to -40c then soak at that temp for awhile then up to ambient and down again. They are repeating this multiple times but the chamber lately takes too long to reach -40 where it could run the profile 7 times a day before now it can only get there twice a day. Low stage had leaks in the past (relief valve on the dump tank).

  8. #7
    Join Date
    May 2019
    Location
    Albuquerque NM
    Posts
    6
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    Thread Starter
    Yeah I should have brought my running info to the forum. It sounds like the first stage needs attention. I think I will start with the water regulating valve on the 404 condenser if the cascade condenser is not subcooling the 508 enough that could mimic a low charge on the 508 side right?

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  10. #8
    Join Date
    Mar 2008
    Location
    kansas
    Posts
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    Not the way I’m seeing this with your high stage not cooling as designed your low stage would act overcharged (no where for the heat to go) I’ve only worked on a couple of espec chambers but they had two txvs for low stage 1 for high stage and a capacity control valve( solenoid valve). Thinking out load here you say a leak,but a restriction will mimic low on gas.
    Honeywell you can buy better but you cant pay more

    I told my wife when i die to sell my fishing stuff for what its worth not what i told her i paid for it

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