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Possessed Sprinklers Turned On By Themselves Today

12 years ago

So, my sprinklers are possessed. Although the water to the sprinkler system isn't shut off (unusually warm weather recently), the sprinkler system is turned off at the control box. I woke up this morning to one of the sprinkler zones in the back running. Turned on completely on its own.


I was looking at the system a few weeks ago since I had noticed some water in the box occasionally a few months ago when they were running regularly. My investigation a few weeks ago found that the front sprinklers (different green, in-ground box than the backyard sprinklers) worked fine, but the rear/backyard sprinklers did not...just an occasional humming from what I believe to be the solenoids.

Today it was raining and the green box was full of water. The wires have water-tight wire nuts on them, but I don't know if one of them has failed. One zone turned on by itself and would not turn off. The control box is in the "off position". I tried the other zones in the backyard and magically they work again -- albeit at a much reduced water pressure because of the one zone that would not turn off.

Anyway, I ended up having to shut off the water to the sprinkler system to get it to stop. Any ideas what's going on here? Seems to me that it's electrical. Does power have to come from the control box for the sprinklers to turn on? Please help.

Comments (9)

  • 12 years ago

    Hello again. I have seven zones (just four in the back where the problem is). Is that many?

    My solenoids are all turned clockwise/off. Is that where they're supposed to be for the controller to activate them and turn on each zone?

  • 12 years ago


    Yes, but to make sure the mechanics of the solenoids are operating properly, complete the exercise I describe before and turn on and off each zone and observe that it actually comes and then goes off by turning the solenoid. Again do not over-tighten, turn clockwise by close only enough for the zone to go off. Let me know what happens. If you replace your controller you would need an 8 or 9 station controller. Aloha

  • 12 years ago

    sorry I have not chimed in on this situation sooner. It sounds like you have two problems, one being a loose common wire connection in the valve box. reconnect it with a new wire nut and things should work normally. The second is the valve turning on by itself. this only happens if debris is interfering with the diaphragm or the diaphragm has failed and needs to be replaced. If water in the box is from runoff and not a leak it is extremely common and not much of a concern as long as all the wire connections are water tight.

  • 12 years ago

    Coils will buzz sometimes when there is no problem this humming/buzzing is not a sign of a problem. Valves typically fail because of a bad diaphram in the valve. This normally leads to one of two problems. First, the valve wont open and the second that it will not close. In both cases if your valve is more than a few years old the best solution and the one that fixes the problem the vast majority of the time is to replace the diaphram.

    Most home systems with multi-station systems have small rather inexpensive diaphrams. If the valve is several years old the parts are past their prime anyways. Often debris get in valves because of work on city water lines or because of dirty water BUT often if the debris get in the valve to cause them to stay open they have somewhat or completely damaged the diaphram anyways.

    One thing to be very careful of is to not let dirt or rocks get in the valve while you have it apart. Almost certainly your going to need to keep the valve apart while you get the diaphram so either reassemble the valve missing the diaphram or cover it so nothing can get inside. Several years ago I left a valve open that was clear of any possible dirt. Over night a frog got inside it and up the pipe enough that I didnt see him.....yea that was a mess.

    Good luck,

  • 6 years ago
    last modified: 6 years ago

    Had a very similar problem with mine - 3 zones and the program set for 8AM, It was in the OFF position and at 2PM or so all 3 zones started watering at the same time, the time on controller was correct. Opened the controller box and had about 25 stink bugs and a slug in it. Killed the bugs and cleaned out. Did a reset on controller. Also the 9V battery was 3 years old - replaced - fingers crossed. They turned off by just moving from off to run and back to off when they had started in the off position. Also did that 2 days ago at a different time. We had a brief power fail a few days ago and that large solar flair probably hit about this time.

  • 6 years ago

    Been behaving now for a month, probably was the bugs!

  • 4 years ago

    Hi all! I moved into my house three years ago and the sprinklers haven’t worked. We have recently been dealing with a leak in our living room and turned the water off at the street. We turned it back on and all of sudden three sprinklers were on. We aren’t sure what to do because we haven’t used them at all and honestly didn’t think they worked. Confused why the would turn on all of a sudden.

  • 3 years ago
    last modified: 3 years ago

    Can somebody please tell me why my sprinklers are turning on in the middle of the night when I do not have any timers to the sprinklers plugged in? Someone said I needed to change these? I am in need of help thank you for your time