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backflow preventer feedwater piping

nevele Member Posts: 30
Can anyone explain the proper order of a bacflow preventer, strainer, feedwater valve with a bypass around it ? It's on a commercial system. thank you


  • Jamie Hall
    Jamie Hall Member Posts: 22,125
    Does this come from drinking water? If so, are you sure you need the strainer? Anyway -- backflow preventer first, the strainer if you really need one, then the feedwater valve and bypass and what have you.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Member Posts: 20,762
    For hydronic applications manufacturers are starting to add strainers right at the inlet of the back flow device. The strainer can help prevent premature failure of the BFD and often prevent leaks as they are turned on the first time.

    BFDs need a bit of pressure to close and seal the vent port, they should be upstream of the pressure reducing valve.

    The bypass is around the PRV, most fill valves have a bypass mechanism built in.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • nevele
    nevele Member Posts: 30
    That answers my question Thank you Jamie and Bob .