Anti siphon valve and check valve

[unhitched]

Hello, I am new here and I found this forum by googling, I am replacing some of my anti siphon sprinkler valves. They are just old and the plastic has become brittle. I wanted to ask about the wisdom of adding some check valves before the anti siphon valves. The reason i am considering this is that most of my sprinkler zones are on a slope and after the zone finishes running there is a significant amount of water comes back through the anti siphon valve and is encouraging week growth around the valves. I understand the best course of action would be to located the valves higher than the highest sprinkler, and I did that at one location but at another it is not really possible and keep them hidden from view. I think by adding a check valve I could reduce the amount of water coming out of the anti siphon valve and encourage the water to run out the sprinkler heads rather than all the way back to the anti siphon valve. is the sound thinking? is there any reason I should not do this? thanks in advance

Nick

 

[Geofd]

Cut the check valve in turn the zone on and see what happens,let it go thru a few cycles before you bury it,you will have to watch it and see if everything functions as designed

 

[unhitched]

these are actually above ground valves that have the vacuum break, so it is not a big deal to access them later. The issue is no that because they are located below the sprinklers and there is a lot of pipe, there is a lot of water that comes out of the vacuum break. I was hoping to eliminate that by the addition of the check valve. I know that the vacuum break is there to stop water from flowing back into the water supply, I just want to make sure I am not creating an unsanitary condition by adding the check valve.

 

[Twowaxhack]

Try it and see, take some pics. Report back what you find.