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New Member


Wednesday, April 4th 2007, 8:05pm

Backflow, Pressure Reducer, Manifold layout help

I have a 1" Febco 850 DCVA, 1" Wilkins 500YSBR Pressure Reducer with y-filter, ball valve, and 3-valve manifold assembly to install for my irrigation system with a measured 95 PSI at the ball valve.

I have tapped into the 1 1/4 poly mainline and have 1" Sch 40 PVC out of the tee into a 1" brass ball valve with the handle 6" below the soil level. Next I plan to add the DCVA and put the ball valve and DCVA in a standard box on a 12" bed of gravel.

Then I will have to run 1" Sch 40 PVC at 20" depth to a second valve box with the 500YSBR and 3-valve manifold. I could run the 500YSBR sideways on one end of a jumbo valve box and come out of the reduced pressure side with an elbow to the manifold. Out of the manifold (valves) I switch to 1" poly and use barbed elbows to get down to 12" depth for my lateral runs. Maybe I could squeeze this into a standard valve box if I don't use the y-filter with the same layout.

Any comments or will this work? Thanks.


Supreme Member


Thursday, April 5th 2007, 3:34am

Damn double checks- I can't believe they are still approved for use for sprinkler systems.

How long is your mainline run? What flow are you designing your zones for?


Supreme Member


Thursday, April 5th 2007, 5:13am

"Bed of gravel..." that's how I should have done it.

I set my system up with Sch40 PVC Teed off the Sch40 PVC main just after the meter. My master shutoff is in a round box by itself about 12+" below soil level just after the Tee from the mainline.

I placed the DC in a large rectangle box (12x16 I think) with a Y-filter. Basically I have the filter on the left side of the box, the pipe then makes a U-Turn with the DC on the right. It's all setup such that all the test cocks of the DC are easily accessable and the filter has room to be removed, cleaned and replaced.

But since my mainline static pressure was only 70psi, I only used a pressure reducer for the part of my system that feeds drip irrigation. To stuff as much in a single box, but leave everything accessable for maintainence, I set up my valves in the mainifold such that a pair of unions mounted vertically hold the valves (i.e. pipe from manifold goes vertical through union, turns 90 to horizontal vavle, then 90 back down toward the ground through a 2nd union). I was then able to run the pressure reducer feeding the mainifold inside of the upside-down U channel created by the series of valves installed with unions. The unions allow me to stuff 4 valves in a standard 12x16 box (i.e. they are mounted closer than usual, but the unions allow them to be removed for maintainence and repair) an allow me to use the space under the valves for the pressure reducer.
I set my system up with Sch40 PVC Teed off the mainline

I set my system up where I had a Y-filter and DC in one box, and valves and pressure reducer in another.


New Member


Friday, April 6th 2007, 3:25pm

The mainline run is 10 feet to the point where I want to place the valves. My rainbird design states flows in each zone are 8.5 gpm, 12.6 gpm, and 3.8 gpm (drip).

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