| Catch it and tie it up! HAR HAR HAR.
No, not really. Seriously, though, most of you guys and many of you ladies may have noticed some urinals running constantly. Of course, this is a waste of precious water and annoying to boot. Fortunately it's easy to fix by you, right then and there. Step up to the podium, intrepid noder and give that urinal what for!
Big damn disclaimer! i am not a licensed flushologist, nor do i play one on TV. this is based solely on my experience. This technique will probably work on all commercial toilet-type thingies (ones relying on water line pressure instead of a tank and gravity).
Right. Now then, the urinal keeps running because something in the valve is sticking open. So to stop it from running, you can either fix the valve or just shut off the water. Since this node isn't entitled "How to dismantle and rebuild the flush valve in a urinal to stop it from running", i'm just going to tell you how to turn the damn thing off, quick and dirty style.
First, orient yourself. Face the offending machinery and look for the piping coming out of the wall. Once it comes out of the wall, the pipes make two 90° bends into the top of the urinal. If this model doesn't have exposed pipes, you're out of luck. What you're looking for should look something like the following horrible ASCII diagram:
(o) - pipe coming out of wall
| |
___ | |
valve & | |____| |
handle | ______)
====| |
\_/
---------------
(top of urinal)
Right. Got it? Good. i knew you would.
Next, look for the valve itself. It is almost always at the end of the pipe that comes out of the wall. Look for a flat face on the pipe that is parallel to the wall. Notice the (o) shape to it? in the center of this flat face will be some sort of recessed disc with a slot in it. That's the water valve adjustment screw. These are sometimes covered up with decorative covers, which are always worthless decorative crap. Get rid of it. These covers can usually be removed by hand, but if not, move along. You've got better things to be worrying about.
Now the adjustment screw is visible, exert some torque on it and close that sucker. That would be clockwise or negative torque if you're using the right hand rule.
Parenthetical thought: (So what are you gonna turn that with? Be resourceful. i almost always have a knife on me, so that's what i usually use. When i worked 3rd shift at Waffle House, i would use the handle of a fork. Keys also work well. Be resourceful.)
w00t! Holy crap, wouldja look at that! It quit running! Congratulations, 007, you've done it again. Now here's a counter-intuitive step - turn the water back on. Give the flusher a pull or two and see if it quits running after it's done flushing. Sometimes, it just needed to catch it's breath and it's right as rain. If it keeps running, turn the water down slooowly. You may reach a happy medium where it has enough pressure to flush but not enough to keep it running.
Congratulations, you have just saved some water. Your Mom should be proud. | 
