Gate valve better than ball valve for irrigation?

[rationull]

My house has a separate water line coming off the meter for irrigation vs house water. That is, there's the meter with a ball valve hanging off the end covered by some dirt in a concrete box, and then the pipe splits into two branches. For some reason whoever designed the system saw fit to make the irrigation branch extend up above ground for 1.5 feet or so, run a couple feet, and then go back below ground. The horizonal portion has the shutoff ball valve on it and the vertical section on the outlet side has a hose spigot.

I drain it for the winter, and both winters I've lived here now the valve has burst on the side where water is trapped between the ball and the outer wall when the valve is shut.

Maybe there's a better method to drain the valve itself that I'm not aware of, or maybe I can find a stronger one or one with a drain vent on it or something. But, it seems like replacing it with a gate valve instead might be a simpler solution. Note the problem is not the pipes freezing (they are wrapped) just the little bit of water trapped in the valve.

Would replacing this with a gate valve just be asking for worse trouble or would it be a "normal" thing to do? Surely there's a simple solution for this problem!

Note I may surround the whole thing with an insulated box in addition to whatever I do with the valve. But, I need to replace the valve anyway now and I figured I should replace it with something better if I can.

 

[Shannow]

Industrially, it's Ball valves FTW in a sut-off situation.

If you've got a dead leg full of water, and it freezes, something is going to pop, ball, gate or globe.

Need to stop the pipe freezing.

 

[hisilver]

Find a way to hook up an air compressor to the system, rig up a little tool to hook into the spigot. I blow mine out every fall so with compressed air so there is nothing to freeze. Also whatever valve you choose buy a brass or metal one, the plastic ones never last as long or are built as good.

 

[rationull]

The pipes themselves are not actually freezing. I have the exposed length that doesn't get drained wrapped and it doesn't get cold enough to be a problem there I don't think. I can drain the outlet side of the ball valve enough that it's not a problem. Nothing I can do about the inlet side except wrap it I don't think because it's pressurized coming off the meter. The problem is the little bit of water that gets trapped in the valve itself when the valve is shut.


But I do plan to address the whole freezing issue by putting this in an insulated box anyway, I think.

 

[Schmoe]

The pipe going above ground is a requirement. There should be an anti-siphon device connected to it, sounds like it wasn't or it was removed. If your pipes don't drain automatically when the water is shut off, then it wasn't installed right. The irrigation lines should have had drain valves installed on them. When the pressure is on, these valves close automatically, when you turn off the water pressure and release any residual head pressure, the valves open up and drain the remainding water into the ground. It gets cold enough, wrapping the pipes will not help, you got to get the water out. Hisilver is spot on, you got to come up with a way to manually drain those lines before winter sits in. I'd put a spigot on just past the water meter. Depending on gravity, open that valve up after you turn off the main water line and open the spigot furthest away from the meter and it might drain via gravity. If not, get a air compressor and force about 10 psi through the system, slowly.

 

[rationull]

I think there is some confusion about what I'm describing here -- either I'm confused about what it is or I'm just not describing it well. To clear it up, here's a picture:

The blue arrows indicate flow direction. The ball valve housing is cracked under where the tag is in the picture. The water meter is 10 feet away from it on the side where the pipe is insulated. This is next to the road and the sprinkler system is 100 feet or so up a small hill next to the house. Please forgive the unprofessional looking taping job, that's mine

So, unless I'm really missing something I can't drain the water from the insulated section of pipe on the left side of the ball valve. I think insulation is the best I can do there. Unless there's some extra buried valve I don't know about, but then what would this section of pipe be for? Just draining the system?

I don't know if the pipes up the hill automatically drain into the ground when the water is shut off or not, but it's possible. How fast is that automatic draining supposed to happen? I do know that after I've closed shutoff valve for a while, if I open it again there does tend to be a rush of water into the system so maybe it is draining, just slowly. When I noted this behavior I assumed the sprinkler heads were just leaking slowly when pressure was cut.

To drain it this year I just closed the shutoff valve and opened the spigot in the picture and let it drain out. I know that won't drain water below the spigot but I figure that the air space in the pipes would be enough to ensure it didn't burst the pipes if the water inside froze.

Is the brass thing on the right hand side of the horizontal section an anti siphon/anti backflow device? It's got what looks like a plug on top and on the side but I haven't tried to open either because I don't know what it's supposed to be doing and didn't want to mess anything up.

I did try to work out a way to shut off pressure and drain the system enough that I could have the ball valve drain completely when it was open, but it would involve shutting off and draining a bunch of house water too and I didn't want to do that if I could avoid it. It seems like there must be something simple I'm just not thinking of...

 

[Blaze]

Mine has a anti-siphon drain as mentioned. I installed mine with a 5-gal bucket (bottom cut out) around the valve filled with drain rock and a piece of plastic on top so dirt would not filter its way back down on the valve and possibly clog it.

 

[mva]

I think you have your answer - given your arrangement a gate valve would be much better. It will not hold water inside like a ball. Plus you should be able to insulate it and still access the handle.

A ball typically gets pushed by the water pressure against the downstream seal, therefore the ball and most of the housing is always full of water. Once it starts freezing the ice trapped inside the ball expands and breaks the valve housing.

If you are willing to change the arrangement there are freeze-proof yard valves available:

link

 

[doitmyself]

That is a check valve to the right of your ball valve and it does NOT count as a RPZ/backflow prevention. Depending on your house plumbing, you could pull contaminated water from your irrigation system into your household drinking water(possible code violation and serious health risk here). You also might consider a vacuum breaker after the "check" valve.

A gate valve will still have some water on the pressure side to allow freezing. Also odd, you state that freezing doesn't occur, yet the valve cracks???

You need something/somewhere on the "upside/pressure side" of your above ground header assembly to turn off and drain the water in a non freeze zone....either below ground near your header or near/in your house.

Study the irrigation forum at lawnsite.com.

If you can shut off this line at the house, just blow out the water at your header location enough to get out the water to a below ground level.

Ball valves are wonderful and are my preferred valve for most applications. They are designed for totally on or totally off, but I use them for "throttling" in my irrigation with the result of "slightly' reduced seal life. Gate and globe valves supposedly handle throttling better. Like all things, import valves are taking over the market and quality is variable.

 

[rationull]

Originally Posted By: doitmyself
That is a check valve to the right of your ball valve and it does NOT count as a RPZ/backflow prevention. Depending on your house plumbing, you could pull contaminated water from your irrigation system into your household drinking water(possible code violation and serious health risk here). You also might consider a vacuum breaker after the "check" valve.

A gate valve will still have some water on the pressure side to allow freezing. Also odd, you state that freezing doesn't occur, yet the valve cracks???

You need something/somewhere on the "upside/pressure side" of your above ground header assembly to turn off and drain the water in a non freeze zone....either below ground near your header or near/in your house.

Study the irrigation forum at lawnsite.com.

If you can shut off this line at the house, just blow out the water at your header location enough to get out the water to a below ground level.

Ball valves are wonderful and are my preferred valve for most applications. They are designed for totally on or totally off, but I use them for "throttling" in my irrigation with the result of "slightly' reduced seal life. Gate and globe valves supposedly handle throttling better. Like all things, import valves are taking over the market and quality is variable.


Scaring me a little wrt the anti-backflow. This setup is a ways from the house and down a hill, not sure if that has anything to do with codes. Maybe I'll have someone from the water company come out to check this out.

Freezing temperatures do occur, definitely. I haven't seen evidence of the insulated section of pipe freezing -- at least, it hasn't cracked. The place where the ball valve cracks is not under water pressure when the valve is closed. It's just the leftover water sitting in the valve.

Unfortunately since this is all outside a ways from the house it limits my options for large no-freeze zone setups. Maybe I can bury something. I think I need somebody who knows about this stuff to come out and see it though.