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spinman1949

Senior Member

Posts: 15

Location: San Diego CA

1

Sunday, September 9th 2012, 3:42pm

Need advice on backflow devices.

This is a common story.

Major remodeling with landscaping. Existing irrigation being adapted. Now I find the need for expert help.

I will make it simple. If I install a RPZ right after my main feed shutoff valve, can I eliminate all other forms of backflow devices? I have one very high slope in the backyard that has gear drive heads on one zone and then I have 2 drip zones with very little elevation change from the rear zone to the valve station. The front zone is below station elevation. If the RPZ will do the trick, then I can go to regular valves. This will make it easier for me to put pressure reducers in the drip zones. On the EZ Flow? I am playing around with using a forth zone for a misting system for the house. So my guess is the way to hook that up is to place it after the valves using a connector on each valve and on the drip zones and I should put the connectors after the pressure reducers?

Am I on the right track?

hi.todd

Supreme Member

Posts: 417

Location: Houston, Texas

2

Sunday, September 9th 2012, 4:13pm

I will address the Backflow Question. Place your RP prior to any zone valves and prior to any injection or EZ Flow. Also after installation, get it tested by a licensed professional. You will have a high hazard application and need to get it tested.

It is brand new why does it need to be tested? Because during the installation debris, copper or PVC shavings, dirt, anything can get it the device and prevent it from preventing backflow. Also if you don't apply the water to it slowly the first time you charge the line you can cause the seats and springs to get out of alignment and prevent your backflow preventor from preventing backflow. The test will usually be from between 50 and 125.00 for a residential application. 8)
:thumbup: :thumbsup:

spinman1949

Senior Member

Posts: 15

Location: San Diego CA

3

Sunday, September 9th 2012, 5:04pm

Great Response !!

Wow !! Thx Todd.

So based on your post I should put a shut off valve before the RPZ and when I first apply pressure do it gradually. As far as testing? I am a fairly accomplished tech in the mechanical world, so I feel confident I can follow any testing procedues given in the manual. But I will check on a prof test. Also what about a filter? I realize the RP will drop pressure and so will a filter to some degree. I have no exact figure, but at present the two drip zones are using retro DIG heads and if I turn the control valve on to full on, the heads pop closed connectors like crazy. So since these units are supposed to work with retro sprinkler systems, I figure my supply pressure is pretty high. I do know that the supply is direct from the street. My house pressure reg and shut off have no effect.

Wet_Boots

Supreme Member

Posts: 4,073

Location: Metro NYC

4

Sunday, September 9th 2012, 7:34pm

No matter what mad skills you possess, you may need a paper trail that a professional tester provides.

spinman1949

Senior Member

Posts: 15

Location: San Diego CA

5

Sunday, September 9th 2012, 10:44pm

Wet_Boots

Gotcha. OK once I get it all done I will call for a professional inspection.

spinman1949

Senior Member

Posts: 15

Location: San Diego CA

6

Sunday, September 9th 2012, 10:49pm

Todd,

You said it will be a high hazard? Why is that? The hill has all above ground heads. Is the high hazard because I plan to us an EZ Flow?

hi.todd

Supreme Member

Posts: 417

Location: Houston, Texas

7

Monday, September 10th 2012, 10:07am

EZ Flow Yes, and Irrigation is considered High Hazard Most of the time.

I would like to say 100 Percent of the time, but some jurisdictions approve the double check valve as an appropriate Backflow device. Double check valves are only for a low hazard situation.

Pressure loss will be anywhere from 8 to 15 lbs depending on flow rates and manufacture of the RP.

Good Luck.

Oh yeah the gauges to test backflow devices are usually about 800.00 :thumbsup:
:thumbup: :thumbsup:

spinman1949

Senior Member

Posts: 15

Location: San Diego CA

8

Monday, September 10th 2012, 10:14am

Todd,

Thx now I understand. And I was not aware there is a guage involved. Not going to spend $800 for sure. I will get a professional.

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