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  1. #27
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    A wider angle picture would be nice. What's said ice pushing against ?

  2. #28
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    The shell.

    Heres what water hammer damage looks like, at least when steam is involved.




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  3. #29
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    How's the vacuum occur ?

  4. #30
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    Quote Originally Posted by VTP99 View Post
    How's the vacuum occur ?
    With steam?

    When steam is contained inside a vessel or pipe, or radiator, when it cools, the water vapors volume decreases significantly. Steam to water volume ratio is roughly 1600 to 1.




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  5. #31
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    Quote Originally Posted by heatingman View Post
    With steam?

    When steam is contained inside a vessel or pipe, or radiator, when it cools, the water vapors volume decreases significantly. Steam to water volume ratio is roughly 1600 to 1.




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    So in this case the water is on the outside of the tubing. Wouldn't that vacuum be pulling on the tubing not pushing in ?

  6. #32
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    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.

    You dont typically eddy current test the tubes on a chiller that has refrigerant inside the tubes. You might if you suspect problems, but its a pretty big to do, vs when the water runs in the tubes.


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  7. #33
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    Could boiling refrigerant be violent enough to cause that?

    Like I said above, I believe water to be inside the tubes, and refrigerant to be in the shell.

    With the machine having been offline for some time, liquid refrigerant would settle to the low point, perhaps the evaporator.

    What would happen if there where suddenly a shock of hot water/glycol sent into the bundle. Like if a 2 pipe system where changed over strait from heating mode to cooling mode with no cool down.

    The liquid refrigerant would immediately begin to violently boil without the pull from the compressor to alleviate any pressure buildup.

    Does refrigerant have enough brute strength to break stuff the way water does?


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  8. #34
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    Not sure what machine he has, but with a cooler of that design, I would expect and ASSume he has a DX system. That being the case, refrigerant inside the tubes, water outside.

  9. #35
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    Collapsed evaporator tubes - anyone seen this before??

    The man said he removed the discharge piping to look inside the bundle.

    That and the copper and steel is way too clean to be the waterside.

    I realize the word discharge does not really go hand in hand with evap, but thats my theory.

  10. #36
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    it's a glycol system, so I could see it being clean. he said air cooled scroll, I don't think anyone makes a scroll chiller with a flooded barrel. screws, yes.....

    it's all speculation without a model......

  11. #37
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    deleted.

  12. #38
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    Assuming that the water is on the outside, I will put in my $0.02. This could be entirely wrong - I am just basing this on what we know.

    First, a perfect vacuum would add less than 15 psia to the differential pressure. I cannot imagine that pulling a vacuum caused this.

    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.

    Or, it came from the manufacturer that way.

    For what it's worth, I cannot tell you how many times I flew to a job site with a high level of confidence that I knew what was wrong only to learn new information that pointed to a different cause.

  13. #39
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    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?

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