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Vacuum breaker

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furnacefigher15
furnacefigher15 Member Posts: 514
in Strictly Steam
I really like using angle pattern check valves as vacuum breakers. Trouble is I cant find a make that lasts more then a year lately. Hoffman and Bell Gossett vacuum breakers dont have the capacity I require, and also dont open at a low enough vacuum level.

What is everyone else using. Ive thought about using a thermostatic radiator trap, but not sure if it will reliably trap steam.

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  • Jamie Hall
    Jamie Hall Member Posts: 23,284
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    What are you using the vacuum breaker for? And at what pressures? And what, if anything, is the outlet connected to?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    furnacefigher15
  • furnacefigher15
    furnacefigher15 Member Posts: 514
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    Low pressure steam. Outlet to atmosphere. I use them on boiler water columns and steam headers. Every now and again I get a system with erradic flooding issues thats is a result from vacuum/vapor lock. So I install the check valves, and that resolves my water entrapment issues caused by vacuum.
  • furnacefigher15
    furnacefigher15 Member Posts: 514
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    Let me rephrase that - outlet of the check valve points to the steam side, so technically inlet is atmospheric
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,293
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    Hello, How hot do you think the check valves that are failing are getting? What is the seal material in the checks, if any, or are they just brass?

    Yours, Larry
    HVACNUT
  • furnacefigher15
    furnacefigher15 Member Posts: 514
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    They probably get around 200 to 225 degrees at peak temperature. Some seats are stainless, some brass, some PTFE. All have been rated for steam service. They have also all been installed within a water seal.

    IE - in the horizontal run of a U shaped trap.
  • Jamie Hall
    Jamie Hall Member Posts: 23,284
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    Most good vents should open on a vacuum at very low differentials -- unless the steam side pressure is too high (many won't open reliably if they are subject to over 3psi on the steam side). In you application here, perhaps the Barnes & Jones Big Mouth might work quite well.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    furnacefigher15
  • furnacefigher15
    furnacefigher15 Member Posts: 514
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    I think that big mouth might be exactly what Im looking for.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,523
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    I like using checks as vacuum breakers as well. I would buy a 300# Milwaukee seems to be pretty good
  • furnacefigher15
    furnacefigher15 Member Posts: 514
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    What kind of longevity are you getting?

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