What's wrong with my sprinkler system?

April 16, 2005 7:20 PM

I suspect that my sprinkler system is going off EARLY every morning without my permission. How can I find out if it is, and make it stop?

Every morning when I go outside my grass is wet. It's the rainy season in Texas so this is not entirely out of the question, but the neighbors grass is generally not similarly wet. This morning I left the house really early (6:30am) and noticed that the sidewalk was wet. No one else on the block had a wet sidewalk.

Also, one part of my yard has a root system that appears to be rotting. This is a symptom of having it wet too long during the night.

The sprinkers are currently set to go off at 8:30am MWF. I am not sure if they do this reliably as the time was chosen to make sure the wife and I were out of the house, and the dogs safely inside. if I set it to go off on a saturday or sunday and wait to see if it does, it does.

The clock is set correctly on the sprinkler system and as far as I can tell it's programmed right.

How can I find out if it really is going off in the middle of the night, and when, preferably without having to stay up all night myself? If it really is all messed up, I guess I'll have to replace it. How difficult is it to drop in a new (possibly different) unit? I assume there is a set of wires for each "zone" in the yard and that I'll be able to attach these to a new unit and just go. Is there more to it than that?

While I'm at it, there is an area of the yard I do not wish to water. Is it safe to just cap these off? I assume it will change the pressure in the system but I don't know how much. I estimate that the heads I'd want to cap off would be 1/3 of the ones on in that zone.

posted by RustyBrooks to Home & Garden (13 answers total)

Response by poster: There's always the possibility I've overlooked something, of course. But my system is very simple. It has an A and a B schedule, and you set which one it is with a switch. Whichever program you have selected, when you rotate a dial around through the days it will say whether the system is on that day or not. When you cycle some more it will say the times. There is only one time set, 8:30, and the only days set are MWF. Further, the B program is exactly the same except all seven days (yay texas summers!)

It's very odd.

The soda can suggestion may work, but we have all kinds of possums, rabbits, squirrels, dogs, cats, etc roaming around so that may hamper a positive ID. I'm *almost* 100% sure it is going off every day. Maybe 98%. The real question is becoming "when"
posted by RustyBrooks at 7:38 PM on April 16, 2005

Zip-tie a plastic bag around one of the sprinkler heads. If it's full of water in the morning, you know the sprinklers went off. (If it's a large bag, you can even figure out roughly how long they ran.) "When" is tougher...You could probably cannibalize one of those "flooded basement" detectors, run wires back to your bedroom, and get an alarm when the water starts. It wouldn't be too hard to hack something like that up from scratch, either. Perhaps you could use the signal to turn on a clock, which you'd set at 12:00 before going to bed. Then you'd be able to work backwards to figure out what time the sprinklers started.
posted by spacewrench at 7:55 PM on April 16, 2005

Another thing: disable the timer completely and see whether the sprinklers are going off anyway. That may save you some headaches before you decide to change the timer. BTW, the sprinkler timers I'm familar with are pretty simple, and not very hard to replace.
posted by spacewrench at 7:58 PM on April 16, 2005

Further to what spacewrench says: My system valves have rubber diaphragms, which will eventually crack and allow water through, even when the timer is off. In this case the problem is not with the timer. You should replace all the diaphragms, not just the leaking ones.

Regarding the rotting roots--does anyone gain by the tree(s) dying? I have a neighbour poisoning my trees for his view. (I may post this to AskMe).
posted by weapons-grade pandemonium at 8:24 PM on April 16, 2005

If you could fnd some sort of timepiece that breaks when it gets wet, then that would solve your problem. Water hits it, time display stops. But I have no idea if such a thing exists and am not clever enough to figure out a way to implement such a device.
posted by Falconetti at 9:58 PM on April 16, 2005

I'm not sure what good it does you to know what time they're going off, once you've established that they are. But to find out when without staying up all night, do a binary search. Say you go to bed at midnight and get up at 8. The first night, set the alarm for four, go out and see if the grass is wet, and go back to bed. The next day, set the alarm for two (if the grass was wet the night before) or six (if it wasn't). And so forth.
posted by bac at 10:19 PM on April 16, 2005

If you use the plastic bag approach mentioned above, you could also put in the bag a cheap analog watch/clock that would stop working within a few minutes of being exposed to water. Ideally you would then just view the stopped time. Of course, uou'd have to make certain the water would only affect the clockwork and not the hands. This is a stupid idea, but hey, it's an idea.
posted by gluechunk at 11:09 PM on April 16, 2005

I think bac's advice is the soundest.

Tho, if we're going for Rube Goldbergish flights of fancy, you could fix a cheap travel alarm clock to the ground with its battery flap cover off, tigh a string around the battery tie the other end to the head of the sprinkler in such as way that the sprinkler head rising out of the grass pulls the battery out of its socket. The next morning, your clock should be suspended on the precise moment the sprinklers turned on.
posted by ori at 11:11 PM on April 16, 2005

Your water bill might give you a clue. If you have last year's bill for the same period, you could compare the usages or at least the total costs.
posted by Cranberry at 12:14 AM on April 17, 2005

I doubt you have this problem but . . . last year I had the same 'symptoms' - grass and soil definitely were damp. Eventually one morning I noticed the driveway was wet. Turned out a slow leak in the main water line had gradually got bigger and bigger and was soaking the soil from below. Had to have it replaced.
posted by Zeedog at 6:22 AM on April 17, 2005

If you had a leak, you'd probably notice wet cement and spongy ground around the clock. It's not hot enough here yet, I don't think, to evaporate before you get home from work. I once lived in a rent house in Dallas in the summer with a cracked main and the little stream down the driveway was pretty much constant.

It might be possible you've got a sewer/graywater drain rupture that's only leaking enough to be noticable after morning bathing (or maybe if you run the dishwasher overnight), but I think that's an outside chance.

If your porch light is bright enough, you could probably set up a webcam to take a snapshot out a window every 15-30 minutes through the night.

Several strategically-placed sheets of newspaper held down with bricks or similar might give you a low-tech idea of whether it's even coming from the sprinklers.
posted by Lyn Never at 9:45 AM on April 17, 2005

Before trying anything fancy, I'd advise simply seeing if the sprinklers are the cause of the wetness in the first place.

It seems to me that the easiest way to do this would be to shut them off completely. Either turn off the timer, or, better, disconnect their water supply. If you do that, and the wetness still recurs, you'll know the sprinklers aren't to blame.
posted by cerebus19 at 10:01 AM on April 17, 2005

On top of shutting off the sprinklers to isolate the problem, if it is "allowable" ie local ordinances, set the sprinklers to come at a time when you will be home, that won't hinder your sleep time. Set them for 6:00 PM, or something similar, and see if the timing mechanism is drifting, or completely off.
posted by AllesKlar at 10:26 AM on April 18, 2005