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  1. #40
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    Jul 2012
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    Did you keep water flowing through the barrel while recovering the charge? If not, the refrigerant boiling off could certainly freeze the barrel.

  2. #41
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    Sep 2019
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    Quote Originally Posted by heatingman View Post
    Im not certain, cause I dont know what machine he is working on, but it sounds to me like the water is in the tubes, and refrigerant is in the shell.
    Water in the shell, refrigerant in the tubes.

  3. #42
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    Sep 2019
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    Quote Originally Posted by coolcoil View Post
    Note that the damage is only to one circuit. I believe that with the leaks the charge in that circuit became low enough that it froze the propylene glycol/water mixture (18 degF freezing point). I think that there was only damage in the return bend area because their is poor water circulation there. In the main body the full flow and turbulence was sufficient to prevent freezing, so little damage to the straight tubes.
    That's exactly what I'm thinking. Multiple freeze/thaw cycles, each cycle the glycol filled the void between the ice and the pipe, and when it refroze it crushed it a little more each time. I believe it is circuited left and right, but the outside tubes froze the worst since the charge was short, causing it to not have a full coil of refrigerant. We want to cut the shell open to see if the piping on the other circuit is damaged, but I'm not sure the owner will allow it. The replacement chiller is being set today.

    Quote Originally Posted by coolcoil View Post
    Or, it came from the manufacturer that way.
    I surely would have thought the installing contractor would have noticed it prior to connecting the CHW piping? Maybe I'm just too gullible??

  4. #43
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    Jan 2010
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    Have you checked your glycol concentration ?
    Attached Images Attached Images  

  5. #44
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    Sep 2019
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    Thread Starter
    Quote Originally Posted by Latestarter View Post
    Just an idle thought, but if there was refrigerant trapped when you pulled your vacuum, and standing water on the outside of the bundle, could you have frozen the water at that point?
    If CHW flow was not maintained, but it was. And I wouldn't think a single freeze cycle could cause that much damage.

  6. #45
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    Sep 2019
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    Thread Starter
    Quote Originally Posted by VTP99 View Post
    Have you checked your glycol concentration ?
    20% propylene, about 19 deg F

  7. #46
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    Sep 2019
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    Also just found out the machine was designed for a 44 deg CHW setpoint, but the owner had it set to 38 deg. Leaning more and more towards multiple freeze/thaw cycles...

  8. #47
    Join Date
    Nov 2001
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    Quote Originally Posted by PAJoel View Post
    That's exactly what I'm thinking. Multiple freeze/thaw cycles, each cycle the glycol filled the void between the ice and the pipe, and when it refroze it crushed it a little more each time. I believe it is circuited left and right, but the outside tubes froze the worst since the charge was short, causing it to not have a full coil of refrigerant. We want to cut the shell open to see if the piping on the other circuit is damaged, but I'm not sure the owner will allow it. The replacement chiller is being set today.
    I would be surprised if it not circuited inside/outside. You want the all of the water to touch the tubes in each circuit so that when only one circuit is running all of the water has a chance to cool evenly. Though, since I cannot see the layout of the shell, maybe you do need left/right to get even cooling.



    Quote Originally Posted by PAJoel View Post
    I surely would have thought the installing contractor would have noticed it prior to connecting the CHW piping? Maybe I'm just too gullible??
    I was mostly joking, but though it is very, very unlikely it is not 100% out of the question. I wouldn't waste time pursuing it, as you couldn't prove it.

  9. #48
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    Aug 2002
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    Southold, NY
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    Checking the freeze point is easy.
    Even with a little glycol it won’t freeze like straight water but becomes more slush!

  10. #49
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    Jun 2007
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    Phoenix,Arizona
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    Quote Originally Posted by PAJoel View Post
    That's exactly what I'm thinking. Multiple freeze/thaw cycles, each cycle the glycol filled the void between the ice and the pipe, and when it refroze it crushed it a little more each time. I believe it is circuited left and right, but the outside tubes froze the worst since the charge was short, causing it to not have a full coil of refrigerant. We want to cut the shell open to see if the piping on the other circuit is damaged, but I'm not sure the owner will allow it. The replacement chiller is being set today.



    I surely would have thought the installing contractor would have noticed it prior to connecting the CHW piping? Maybe I'm just too gullible??
    i agree with this , ice will crush pipe like nothing else
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  11. #50
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    Apr 2014
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    USA
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    I've seen this one time and was due to the water pressure exceeding the maximum allowable pressure. The customer had a chiller with glycol and didnt have any room for expansion during off cycle.

  12. #51
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    Aug 2006
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    My Company took on a job where the Evaporator Froze while Running. It sheared the Refrigerant filled tubes off where they went through the end bells. Barrel came out, and was repiped at a machine shop, meanwhile we replaced one Compressor, dehydrated the other one. Punched holes in the lowest part of the Air cooled Condenser, to drain the water out. Rebrazed the Condenser, and vacuum with a huge double belt driven vacuum pump. All this in the middle of the Winter, with unit tented, and blast heaters running. It was a hospital, and we never left the job for a week and a half.
    Retired, after 43 Years

  13. #52
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    Apr 2003
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    St. Louis
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    Every bundle that I've seen that froze the collapsed tubes were closer to the tube sheet on the feeding side of the ex valve. Also funny that the tube collapse was all on the inside of the curve where the tube thickness would seem to be thicker that the outside of the curve.

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