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gaseous cavitation and glycol solutions....

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deek
deek Member Posts: 21
in THE MAIN WALL
Hi all

I have a circulator that makes a bit of noise and I suspect dissolved air might be the problem.  I just dont know what to do about it.  It doesn't really cause any issues with the system but it bothers me and I am concerned it will cause premature circulator damage.  I was wondering if maybe the 50/50 glycol water mix could be part of the problem?  Is there any connection between glycol concentration and the amount of dissolved air in a system?

A few details about my system...I have a b&g micro bubble separator in the primary loop and  automatic air vents in all the high spots.  There are two heating zones and dhw on priority.  Only one of the two space heating zones makes this noise and when I swapped the the circs, the problem stayed in the same zone.  The system runs at 18 psi and has been operating for the winter season flawlessly...except the annoying noise which seems to get louder as the system approaches the maximum design temperature of 165f.

Any ideas?

Thanks

Derek

Comments

  • icesailor
    icesailor Member Posts: 7,265
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    Glycol Gaseous Cavitation:

    Read this article and understand it.

    I think it contains all the answers that you might be looking for.



    http://www.solarbair.com/articles/glycolarticle.html
  • knotgrumpy
    knotgrumpy Member Posts: 211
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    My wife

    Won't let me into the house when I'm experiencing gaseous cavitation.



    Sorry.  Between the noisy gas valve thread and this one...
  • icesailor
    icesailor Member Posts: 7,265
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    Good Reasons

    She probably has good reasons for doing so.

    When I make Kale Soup, my wife eats it too so she can't blame me for excess gaseous cavitation. She is just as bad.
  • Jamie Hall
    Jamie Hall Member Posts: 23,330
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    A quick question...

    you are pumping away, are you not?  Because, if not, a glycol/water mix is just as apt to cavitate as straight water...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • deek
    deek Member Posts: 21
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    pumping away

    Here is a picture of the system.  The expansion tank is out of view but tees in just before the circ on the return line going to the boiler.  The circ responsible for the noise is the top one going to the manifold.

    The article on glycol was a good read.  I think i will thin it down to 30 percent to lower the viscosity.  Its certainly worth a try.  I dont realistically need -40 protection anyway.

    Cheers

    Derek
  • icesailor
    icesailor Member Posts: 7,265
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    Percentage Solutions:

    I'm glad you read that carefully and picked up that fact.
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