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  #11  
Old 09-26-2013, 09:35 PM
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The actual maximum flow ratings for backflow preventers matches that of water meters of the same size, and that is way off the charts compared with what flow rates you will actually be working with. You can get away with high flow rates in PVBs and DCVAs much more than you can with RPZs, which will spit water from the relief valve when a downstream valve slams shut.
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  #12  
Old 09-26-2013, 09:46 PM
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jbailey52 jbailey52 is offline
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So can someone explain a little more to me... If you use a 3/4 backflow on a 5/8" meter, what size pipe is feeding the backflow, and which leaves the backflow? All 1" with 3/4" fittings for the backflow?
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  #13  
Old 09-26-2013, 10:06 PM
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Not enough information. Variables include length and diameter of the supply line going into the meter, and from the meter to your point of connection.
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  #14  
Old 09-26-2013, 10:41 PM
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I don't get it, the price of a 1" vs 3/4" asembly is minor, it should be run from the setter in brass and a sch 80 mip to tie into the downstream main. Anyone who runs 3/4" mainline joins the hall of pikers and hacks. I wrote the regs for my purveyor and specified unions on both ends.
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  #15  
Old 09-26-2013, 11:21 PM
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The price of brass being what it is, I could see a 3/4-inch full-port system shutoff valve and 3/4-inch DCVA with a 12 gpm flow. Of course, it used to be that most 3/4-inch DCVAs were using the same body casting as the 1-inch ones.
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  #16  
Old 09-27-2013, 09:26 AM
txirrigation txirrigation is offline
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Quote:
Originally Posted by Mike Leary View Post
I don't get it, the price of a 1" vs 3/4" asembly is minor, it should be run from the setter in brass and a sch 80 mip to tie into the downstream main. Anyone who runs 3/4" mainline joins the hall of pikers and hacks. I wrote the regs for my purveyor and specified unions on both ends.
We install 3/4 and run a 1" main. We limit all systems to 12gpm. It's had worked great the last 3,000 times we've done it...
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  #17  
Old 09-27-2013, 12:55 PM
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Quote:
Originally Posted by Mike Leary View Post
I don't get it, the price of a 1" vs 3/4" asembly is minor, it should be run from the setter in brass and a sch 80 mip to tie into the downstream main. Anyone who runs 3/4" mainline joins the hall of pikers and hacks. I wrote the regs for my purveyor and specified unions on both ends.
We don't use dcva's. Cant , illegal here. Difference between 3/4 and 1" pvb is so small its not worth stocking more parts. Not to mention my fingers don't fit inside a 3/4 to rebuild.
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  #18  
Old 09-27-2013, 01:20 PM
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Quote:
Originally Posted by AI Inc View Post
We don't use dcva's. Cant , illegal here. Difference between 3/4 and 1" pvb is so small its not worth stocking more parts. Not to mention my fingers don't fit inside a 3/4 to rebuild.
Can't do dcvas here either.
3/4" PVbs are the most used here, then 1" PVB, then 3/4" RP. Rarely see a 1" RP.
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Old 09-27-2013, 01:55 PM
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Although I will admit when a rp fails and it will, we replace em with dcva's
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  #20  
Old 09-27-2013, 02:17 PM
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Although I will admit when a rp fails and it will, we replace em with dcva's
Obviously, you have no adult supervison, that is crossing the line.
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