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Sunday, June 11th 2017, 9:20pm

1 zone of 7 has low pressure

Just joined - great to have help for DIY'ers. I'm over my skis with this as it's my first experience with lawn sprinkler systems. Thank you.

I have a Lawn Genie lawn sprinkler system that has worked for 17 years after buying a house that is 6 years older. It has two controller boxes in the front that run off the water supply to the house, and another two controller boxes on the side of the house that runs off the same using a long pvc pipe that runs almost across the entire house.

I know nothing about sprinkler systems and reading many posts here has been a big help except that I don't follow some of the technical terms so if someone can indulge me on what is and what may not be a problem that would be very helpful.

1. Each of the two control box locations has a big square control box with 3 valves inside and a small circular one with one valve inside. 3 of these control boxes are filled with dirt up to the top of the solenoids except for one of the big square boxes (not the problem one) which is empty (no dirt which was nice as I can see how it is all connected). Each of the 2 big control boxes has one solenoid/valve above the other two. Not sure why - may be of no consequence or maybe just for more room for the installer. The lower 2 of the 3 solenoid/valves were the one's that were under dirt. So I am guessing the installer intentionally filled the control boxes up with dirt?

2. The zone that has the low pressure problem is likely in the big box of 3 valves since it had lots of water in it and it was the only one with water and mud. Since I initially knew nothing about these I started to dig around and pulled out enough dirt and some small roots (a square foot of dirt perhaps) to see the solenoids and most of the valve assemblies on all 3. As I dug I ran into a lot more water and removed it with a coffee cup as well. I was then planning to turn on the system and see which one was leaking (if so) and where, but when I returned the control box "before" I turned the sprinklers on to test them about an hour later the box was full of new water. Almost a foot of water to the old dirt level that I took out. So now "I think" there is a leak some place in the water path of that low pressure zone. I don't think it is the main supply line connection, at least yet, since the other two zones housed in that control box work fine; and I have only the one zone with the low pressure problem (it runs at about half pressure I would guess from the distance the water sprays out of the sprinkler heads).

3. I now think I may have been hearing a faint 'odd' sound when the sprinklers were running inside the control box when I first discovered the low pressure in that zone, but it was faint and under all that dirt and barely audible. So the sprinkler system does not have to be working to leak. But there is no sound when the sprinklers are turned off as I was digging the dirt out yet the leak clearly was actively leaking to fill the control box back up when I came back after that hour. So what I could use some help with is what I should do next to locate exactly where it's leaking and of course what to do about it? Reading some posts here may suggest just changing out the solenoid since that seemed pretty easy from a post here, and I can see them. Though I suppose a stuck partially open valve may be more likely? Maybe the solenoid could cause that too and that was the sound. It would be nice to avoid digging more dirt out (mud now) to make the entire apparatus visible since I am not anywhere near the bottom of the control box and space is very tight. I'm also a little wary of all that water within a few inches of the basement wall and some hole where the supply line must run through the basement cement wall so I shut off the water to the sprinkler system for now. Probably get up when I am done typing drain it too.

So what part(s) do you think could create this leak? And which should be checked out first? And I have to ask how to check them out as well. Seems like the control box refilling back up with water in about an hour could help with the diagnosis? It's now a couple of hours after I turned the water off and I went out to have a look see and about 80% of he water has drained out of the control box.
So it must have been leaking when the sprinklers were running to result in the pow pressure.
And it must have been leaking when the sprinklers were turned off to refill the control box up with a foot of water.
So it must have been leaking all the time. But there are no signs of water leakage anywhere around the control box or lawn.
Also, it's the following morning now and I looked it over again with some sunlight reaching inside the control box and almost all the water is gone from the control box AND I see a steady small drip running down the pcv pipe from the service side (not the side the solenoid/ water flow control/ and flush scree is on which is the supply intake side. (Hope that makes sense).
The model number on top of it appears to be L7034 which appears with the Lawn Genie name on top of the side that is leaking (perhaps this is a anti-siphon control like on a hose faucet? It looks like the top of this side is a cap and perhaps a twist off. If so, are there parts to replace the inside? I would really like to avoid replacing the whole valve assembly as there is so little room to cut the pipes and I'm not sure exactly how the installer got it in and there may not be enough room to twist off either of the sides.
Many thanks,'

This post has been edited 3 times, last edit by "tbarb" (Jun 12th 2017, 11:39am)



Posts: 2,307

Location: USA


Monday, June 12th 2017, 1:11pm

You possibly have a variety of issues going on.

First of all you have anti-syphon valves down in the ground below grade. Nope you're not supposed to do that. It's a hazard to the city water supply.
Having anti-syphon valves under the ground like that can cause flooding while the valve is running especially if the box is full of dirt.

Anywho, you need to shut the water supply off to the system, then dig the box out of the ground. Nope the installer didn't fill the boxes with dirt. Some sort of animal did. So, turn the water off, dig up the box, turn the water back on and locate the leak.

The strange sound isn't related to the leak because the leak is 24 hours a day and the sound only happens when the valve is running.

After you have it dug up and located the leak you can post pictures if you need help fixing it. Go to, upload your pic there then cut n paste the "forum code" here.

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