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Thread: Canít maintain the glycol level??

  1. #1
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    Canít maintain the glycol level??

    So Iíll try to make this short but giving you as much info as possible.
    So I have a winus unit at a wine factory. Itís an Italian glycol chiller. So itís not cooling enough. I attached a drawing of the piping layout. In the evap tank the evaporator stays sticking up out of the glycol 1/2 way. So it will never cool like this. Only 1/2 of the evaporator is cooling the glycol. So when I unscrew the top fill port on the evaporator tank it has a lot of positive pressure. So I purge it out from the cap. I unscrew the cap. The glycol level never rises higher. That is weird being that itís at the lowest point. So I put my hand on the cap fill port to see what happens. The tank starts to build pressure right away. Not like a lot of pressure immediately but it starts creating pressure. If I turn the glycol pump off. Then the glycol does drain down filling the tank. So I allowed it to fill the tank then I screwed the cap back on. I started the machine again. After 1 minute I checked the tank again by opening the cap again. Sure enough it has pressure again. Itís only circulating glycol. I donít see how it can build pressure unless 2 things. Letís say the evaporator is leaking refrigerant. But the machine has been doing this for atleast 2 weeks. The sight glass is full and pressures look good. At this rate the machine should have lost the refrigerant. Or if the suction of the pump is leaking and the pump is sucking air into the system. But I do not hear the pump cavitating. Pump sounds good.
    We are new to this account. Not sure how it ran prior.
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  2. #2
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    Has this ever worked properly?

    Whats the glycol pressure that chiller produces?

  3. #3
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    A picture of the tank would be nice, it sounds like you have a closed loop system, which will have pressure on it.

    Is there a bladder tank on the return side of the glycol piping?


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  4. #4
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    Ive seen setups like this before, small ID pipe and high pressure. Unfortunately most fermentation tanks are rated for 15# max.

    It may have to be re-piped Pirmary / Secondary.

  5. #5
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    Quote Originally Posted by BadDaddy420 View Post
    A picture of the tank would be nice, it sounds like you have a closed loop system, which will have pressure on it.

    Is there a bladder tank on the return side of the glycol piping?


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    I will try to get some photos of the whole system. Itís not really in my usual route. I do not recall seeing a bladder tank.
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  6. #6
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    Quote Originally Posted by pecmsg View Post
    Has this ever worked properly?

    Whats the glycol pressure that chiller produces?
    I donít know the psi of the glycol side. I believe it worked right before. I was called out about 2 weeks ago. The chiller was down on low pressure. The pressure was fine. But the pressure switch was bad. The customer had a few miscellaneous parts so I swapped the pressure switch. I did notice the glycol level was low. But I told him let in run and see how it goes. He said it was working good. But now it stopped cooling once they opened another isolation valve to add another tank.
    I was working on another unit so the maintenance guy started adding glycol. He said he stopped adding because the because glycol was coming out at the top of the high 4Ē pvc pipe. I can see the high 4Ē pvc pipe is sweating. So it tells me it has cold glycol in it. So Iím thinking 2 things. Itís like an open loop cooling tower installed at the lower level. Once the pumps kick on it will require more water to properly fill the system. When the pump shuts down the water wants to drain out to the lowest opening or level. The same thing could be going on with this glycol chiller. It could explain the lower glycol level. On the other hand if the glycol on the positive side is rising all the way up out the 4Ē pvc pipe means the return side piping going back to the glycol tank has to be clogged/restricted. In theory There is no way the glycol can rise up that high and not fill the lower section. Iíll try to make it back out there to look around and play with a few things.
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  7. #7
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    Quote.
    ...But now it stopped cooling once they opened another isolation valve to add another tank. ......End quote.

    I'd would start there.


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  8. #8
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    Quote Originally Posted by icy78 View Post
    Quote.
    ...But now it stopped cooling once they opened another isolation valve to add another tank. ......End quote.

    I'd would start there.


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    [QUOTE=icy78;25938056]Quote.
    ...But now it stopped cooling once they opened another isolation valve to add another tank. ......End quote.

    I'd would start there.

    I understand where your coming from. But it was cooling when I left it 2 weeks ago. Yes I did see the glycol level was low. Half of the evaporator is stick up out of the glycol. (Not really doing any refrigeration) so with only using 1/2 the evaporator it can maintain 1 tank. But adding 2 tanks 1/2 of the evaporator wonít do it. I feel first I need to keep the whole evaporator submerged under glycol. Then I can start to look at the refrigeration side if it still does not cool enough,
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  9. #9
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    Anthony, Bladder Tank or diaphragm tank?

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    [QUOTE=anthonyac1;25938071]
    Quote Originally Posted by icy78 View Post
    Quote.
    ...But now it stopped cooling once they opened another isolation valve to add another tank. ......End quote.

    I'd would start there.

    I understand where your coming from. But it was cooling when I left it 2 weeks ago. Yes I did see the glycol level was low. Half of the evaporator is stick up out of the glycol. (Not really doing any refrigeration) so with only using 1/2 the evaporator it can maintain 1 tank. But adding 2 tanks 1/2 of the evaporator wonít do it. I feel first I need to keep the whole evaporator submerged under glycol. Then I can start to look at the refrigeration side if it still does not cool enough,
    Yes, glycol level first.
    I thought the level changed when the other tank was brought on line. My bad.

    However, still unclear if it worked before as you found it. BUT, now that theyve added another tank, it doesnt keep up.
    This is critical because it wouldve "always worked before".
    But now it's different (with the added tank and won't keep up.
    That would make the Ĺ covered evap a "normal" situation. If that were true, then it's probably time to look at system design, not, what drain is restricted, or what pump was partially throttled and now isnt, etc.

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  11. #11
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    Quote Originally Posted by TechmanTerry View Post
    Anthony, Bladder Tank or diaphragm tank?
    No bladder or diagram tank
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  12. #12
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    Ok so my drawing was wrong. I assumed the 4Ē pvc was on the supply side of the piping. The 4Ē pvc is open at the top. Also itís on the return back to the pump. I got an extension ladder and went to the top to confirm. So that is an obvious place for air to get sucked into the system. I think someone swapped the hoses at the machine at one point. Iím at the facility now. Iím going to swap the hoses and see if their is a difference.
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  13. #13
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    Thats the wrong way to pipe that job.

    Always look at where the Air will travel as far as flow. Water in at the bottom, out at the top. Never run down to the return line. Continue the flow slightly up where a manual vent can be installed.

    Sch 40 PVC is not what you want, as it gets cold it gets brittle! I prefer Copper!

    is this the chiller? https://www.winus.it/public/docs/1162013111747.pdf

  14. #14
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    Quote Originally Posted by pecmsg View Post
    Thats the wrong way to pipe that job.

    Always look at where the Air will travel as far as flow. Water in at the bottom, out at the top. Never run down to the return line. Continue the flow slightly up where a manual vent can be installed.

    Sch 40 PVC is not what you want, as it gets cold it gets brittle! I prefer Copper!

    is this the chiller? https://www.winus.it/public/docs/1162013111747.pdf
    We use a lot of schedule 80pvc.

    But that piping is a hot mess. Lol.


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  15. #15
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    I prefer Copper but Sch 80 will take the cold.

    They think there saving $ but when it comes insulation time they learn!

  16. #16
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    There are manual vents at the top of each tank on the return water piping
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  18. #17
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    Quote Originally Posted by pecmsg View Post
    There are manual vents at the top of each tank on the return water piping
    Nice set up 👍🏻.

    So having the system open on the return side should not be a problem? Or with the manual vent/valve you fill the system with glycol then vent it. Once your done close the valve. Iím guessing that will be the idea.
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  19. #18
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    So I swapped the piping at the machine just to see if the glycol evap tank with fill with glycol but no itís the same thing. When I made the previous return line now become the supply side. The big vent pipe started over flowing with glycol out the top. But yet the glycol evap tank at the bottom is still running very low. So that tells me the pump is pushing the glycol out but itís not returning fast enough. So I valved off the discharge about 1/2 way now itís keeping a full glycol evap tank. I figured that will do the trick. But after letting the machine run through the night the glycol got down to 38 degrees. My suction pressure was 35 degrees with 11 degrees superheat. It had a clear sight glass. Iím not really sure what the superheat is on these types of systems. But I would assume itís a low superheat. Itís a packaged unit. So I might pull out the charge and re weigh it back into the unit. I started talking with the guy more. I donít think it ever reached the desired temp of 23 degrees f. Before he said it was working the first time I left. But it sounds like 37 degrees is really all it ever reached.
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  20. #19
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    As far as SH at the compressor 20 - 40*F. With that said G D Chillers wants 25 on some of thereís.

    Whoever piped it didnít know what there doing.

    Put valves on those open lines, use them as air bleeders. Closed when not needed. Anything on the chiller to prevent over pressurizing the tanks?

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