Irrigation check valves

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  #1  
Old 06-27-18, 12:32 AM
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Irrigation check valves

This might be a matter of semantics, so apologies if so. To me a check valve only allows water to flow one direction. Yet am I correct in understanding that a sprinkler head "check valve" is more like a low pressure seal in that when the system is shut off some force (probably a spring) closes to hold the water in against minimal head pressure.

Trying to figure out whether I can incorporate a "check valve" in my drip system.
 
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Old 06-27-18, 01:54 AM
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Are you referring to an anti siphon valve, ie check valve?

Anti siphon prevents water from flowing back into the potable water system, a sprinkler/drip system really doesn't need a check valve!
 
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Old 06-27-18, 09:52 AM
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Not an anti siphon valve. Ex. https://www.irrigation.org/SWAT/SWAT...ck-Valves.aspx. There are plenty of videos about them also.

Even in this description it talks about water only flowing one way which doesn't make sense. If it is some sort of spring pressured seal when off I might be able to use one, it's the "one way flow" description that has confused me on how it works in a irrigation setting.

https://www.amazon.com/gp/product/B0...=ATVPDKIKX0DER
 
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Old 06-27-18, 10:00 AM
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Actually rereading the link I guess it is kind of a check valve. Though again to me, a check valve is to prevent reverse flow vs just stopping flow at low pressure.

So I guess I'm left with physically looking at one to confirm if it is some type of spring pressured shutoff. If so I can probably use it.
 
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Old 06-27-18, 01:48 PM
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So again I will ask!

Are you referring to an anti siphon valve, ie check valve?

Anti siphon prevents water from flowing back into the potable water system, a sprinkler/drip system really doesn't need a check valve!
 
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Old 06-27-18, 02:24 PM
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It is a minimum pressure valve. It is built as a normal in-line spring loaded check valve and the spring holds the valve closed until there is a certain amount of pressure at the valve inlet, maybe 10 psi.

The purpose is to prevent the sprinkler head from dribbling after the water is turned off. This dribbling can be a result of the underground piping not being absolutely level and therefore having a slight head pressure on any sprinkler heads that are lower than some other part of the system.
 
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Old 06-27-18, 04:14 PM
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Do you have a drip system or conventional pop up or geared sprinkler heads ? Do you have electric valves and timer ? If you install the Hunter check valve at the low end....maybe any water will divert to the next lowest sprinkler head.
 
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Old 06-27-18, 04:17 PM
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Originally Posted by Marq1 View Post
So again I will ask!

Are you referring to an anti siphon valve, ie check valve?

Um....I did answer in my reply post "Not an anti-siphon valve", which is a "true" check valve in that I know it only allows water to flow one direction.

Thanks Luana, that what I was figuring but the check valve terminology got me wondering. I guess it's easier to say than "minimum pressure valve".

The good thing is I think with knowing how it works, it'll work for my drip system in preventing the supply pvc from draining water up to the drip hose connection.
 
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Old 06-27-18, 04:21 PM
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Originally Posted by YaddaYadda View Post
Do you have a drip system or conventional pop up or geared sprinkler heads ? Do you have electric valves and timer ? If you install the Hunter check valve at the low end....maybe any water will divert to the next lowest sprinkler head.
I have both controlled by valves and timers. It's the drip part of my system that drains out. I'd probably buy the "minimum pressure" sprinkler heads if I was having issues with them as I think your right about the water just finding the next lower head if I used a Hunter check valve on one of them.
 
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Old 06-28-18, 04:54 AM
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preventing the supply pvc from draining water up to the drip hose connection.
You are still getting the devices mixed up, a check valve is intended to keep flow in one direction within a plumbing system, an anti siphon keeps material from being sucked back into potable water systems.

They are not the same and a check valve does not meet the requirements for a anti siphon valve since very low flow, below the check valve rating, can occur.

You need a Watts style siphon valve at the water source.

https://www.doityourself.com/forum/a...1&d=1530186883
 
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Old 06-28-18, 02:44 PM
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Originally Posted by Marq1 View Post
Are you referring to an anti siphon valve, ie check valve?
Here you list check valve as an example of a siphon valve?????? Not sure if that's what you meant to say. It doesn't follow your other posts.

I have anti-siphon valves already, don't need more of them, know what they do.

The Hunter inline check valve (more accurately known as a minimum pressure valve - Luana) connected at the point where my drip tubing connects to the PVC supply should work to prevent the PVC supply from draining out when the system is shutoff. Luana answered the question and cleared it up for me. Thanks for the feedback.
 
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Old 06-28-18, 05:07 PM
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Just wondering but what difference is it make if the water drains out of the PVC feeder lines? They are going to refill very rapidly when the valves are opened again. Adding a low pressure valve (whatever else you want to call it) is just another silly go wrong with the system. The KISS principle certainly applies here..
 
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Old 06-28-18, 08:39 PM
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Is the problem in the electric valve.....? It is not shutting off completely when the timer station is shut off or advanced. ??
 
  #14  
Old 06-28-18, 11:34 PM
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No, the valve shuts off. The water in the PVC pipe from the valve to the drips just drains out because of elevation change.

The difference it makes is water hammer. When the valve opens, all the water floods the line until it hits the drip then it slams the plumbing, which in the long run is not a good thing, in addition I can hear it in the house. It's the only zone that does it. If it was a bunch of spray heads, prob wouldn't have the hammer as the water has a relatively large place to exit the system. A drip zone is basically like slamming a valve closed after the pipe fills.

Of course it's good to prevent the drainage out of a spray system also as aside from wasting water, you can get erosion around the spray heads as they leak out. This however is not my issue. (The drips just water a little longer)

I've installed one of the Hunters on the system charged up the zone. It'll activate tomorrow morning so I'll know whether it worked. I'll update when I know.
 
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Old 07-10-18, 10:23 PM
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Oops. Forgot to update...

I've eliminated prob 90% of the sound. The drips start almost immediately now when the valve turns on. Yea!
 
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