Announcement

Announcement Module
Collapse

How To Post Images

Want to know the how to upload images to your posts? Image Posting Tutorial
See more
See less

Back flow preventers

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Back flow preventers

    How do you know when your going to need an expansion tank when you put in a back flow preventer, just wait and see if the relief valve opens on the HW tank? Any other additional equipment installed with RP's or DCVA's?

  • #2
    Re: Back flow preventers

    By code you always need an expansion tank when a BFP is installed.
    sigpic

    Comment


    • #3
      Re: Back flow preventers

      when there is a check valve on the system or backflow preventer. also if the incoming pressure prior to the regulator is at a pressure equal or greater than the relief valve setting. (150psi).

      most modern regulators have a thermal expansion bypass.

      an easy way to test is to install a hose bibb pressure gauge on the water heater and watch the gauge when the heater is heating with no other use in the house. the pressure will go up and should equalize to the street pressure.

      if you have any form of backflow preventer/ check valve, the pressure will surge beyond the street pressure. keep in mind that the longer the heater runs, the higher rate of expansion, especially with winter cold water.

      if in doubt, install the tank. air charge it to the current regulated pressure or slightly less by a couple pounds.

      rick.

      p.s. welcome to the ridgid forum
      phoebe it is

      Comment


      • #4
        Re: Back flow preventers

        to the Forum.

        It really depends on what Code you are working under. If you are working under the IPC see post number 2. If you are working under the UPC see post number 3.

        Mark
        "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

        I never lost a cent on the jobs I didn't get!

        Comment


        • #5
          Re: Back flow preventers

          if you want a simple answer, see post #4

          good morning mark

          rick.
          phoebe it is

          Comment


          • #6
            Re: Back flow preventers

            thanks for the response. I have few of these BFP's to install in some of the municipal buildings ( arenas, fire halls, public pools, etc).Some of the buildings have a 2" water service that reduces down right at the water meter to 1". For those I was thinking I'd put a 1 1/2" BFP and water meter on then reduce down to 1" so I would'nt lose to much pressure. Make sense to anybody?

            Comment


            • #7
              Re: Back flow preventers

              Originally posted by NHMaster3015 View Post
              By code you always need an expansion tank when a BFP is installed.
              Unfortunately that's not true for us in Canada. Not a code requirement.
              West Trail Mechanical Ltd
              Service. Commitment. Expertise.

              www.westtrailmechanical.ca

              Comment


              • #8
                Re: Back flow preventers

                Doug I'm assuming you're in Ontario?
                West Trail Mechanical Ltd
                Service. Commitment. Expertise.

                www.westtrailmechanical.ca

                Comment


                • #9
                  Re: Back flow preventers

                  Yes, indeed. I took the BFP course and I believe the municipality decides on the code parameters.

                  Comment

                  Working...
                  X