SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I had help installing a sprinkler system several months ago from a guy that I found on line. I have never been completely happy with the results and lately my sprinklers have taken on a life of their own. After the sprinklers come on and go off a short while later (could be a few minutes or an hour) the system makes a thumping/sucking sound and water surges from the sprinkler heads. You can actually feel the vibration under the ground - if I turn off the water at the main sprinkler cut off the problem stops but I need to get the problem resolved. The same problem occurs when I use one hose bib that the sprinkler guy installed at the same time that provides water to my pot bellied pig. When it first occured I called my local water companies emergency number because it started at 10:00 on a Saturday evening and the water company had moved the main shut off at the street and the guy that came by mentioned an air lock - but I really can't find any information on those. Does anyone know what this problem might be called and what I can do to resolve it? The sprinkler guy said its an easy fix but he has a minimum charge of $75.00 to come out and since I have never been happy with the system I just can't bring myself to pay him any more than I already have. Any help/suggestions would be greatly appreciated.

There was an existing system that we just replaced with new pipes and valves after the old system was destroyed by me when i used a ditch witch to dig a new sewer line for a guest house that was built - the only thing that didn't exist before was the hose bib to Pepe's pen. I will check out water hammer and see if that fits and hopefully I can find a way to fix it. Thanks for everything...

I found this and this makes more sense then the water hammer idea - at least given my experience with the noise - the noise will continue forever unless I turn the water off to the entire system. I noticed when they were installing the sprinklers they appeared to be at different heights depending on who was digging the trench - so this explanation that I found on line makes sense to me although I am not sure if it is only one valve so I am going to try this tomorrow.

If the noise only occurs when an individual sprinkler valve (always the same valve) is opened the air may be in the lateral pipe (the pipe downstream of the valve.) In that case you will need to temporarily remove some of the sprinkler heads on that valve circuit in order to increase the water velocity. Remove the 3 sprinkler heads furthest from the valve and then open the valve to flush out the air. If that doesn't get it out try removing more sprinklers. After the air is flushed out, put the sprinkler heads back on. If that fixes the problem temporarily but it returns after the next time you irrigate, then the problem is that the water is draining out of the pipes through the sprinkler heads after each irrigation. This is probably because one or more sprinkler heads are lower than the others. When the water drains out, air gets back into the pipes. To prevent this you need to install "anti-drain check valves" at the inlet of each sprinkler head. The anti-drain check valve is a small spring-loaded check valve. The check valve holds back the water so it doesn't drain out. It does not effect the performance of the sprinkler head noticeably. Many sprinkler heads are available with this feature built-in to the sprinkler. Some brands also have retrofit kits available that allow the check valves to be easily installed in existing sprinklers. The built-in anti-drain check valves do not effect the performance of the sprinkler at all.

I know absolutely nothing about sprinklers and so you are probably correct but the part that I found confusing was that what I read gave me the impression that water hammer made the thumping noise one time when the water shut off. My problem will go on for hours until I shut the water off at the main - thumping/sucking sound every couple of seconds with water surging from the sprinklers. As a matter of fact I fully expect to find it making the noise when I get home and the sprinklers would have shutt off over an hour ago.

With my limted knowledge in this area I think the surging makes sense. When the system was installed last year the guy said that I almost had too much water pressure. The hose bib that he added in my pigs pen has so much water pressure that it can almost take off your skin when you turn it on. Normally when I fill Pepe's water pan I have to go turn the water off at the main to stop the sprinklers from making that sound and squirting out water. Yesterday I only opened the faucet half way and was very surprised when it didn't set off the sprinkler issue. I have a pressure valve - but it is quite old so I think I will have that replaced when the plumber comes out to do some other work in the next couple of weeks. Again thanks for all of the help - it is so nice to have a resource like this - especially in todays economic times when I certainly can't afford to spend any money that isn't absolutely necessary.