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back flow preventer with or without atmospheric vent

ron Member Posts: 148
what's the purpose of the atmospheric vent in a back flow preventer?
such as the watts 9D with the vent, and the LF7RU2-U2 without?
why would you bother using one with a vent?

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  • Jamie Hall
    Jamie Hall Member Posts: 17,823
    The vent is there to help mostly if the downstream check fails. It's part of the safety features of the BFP, and I wouldn't use one without it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Mad Dog_2
    Mad Dog_2 Member Posts: 3,471
    Its a higher degree of protection. Mad Dog
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