I have an 8-zone, in-ground sprinkler system. There is a 1″ copper pipe that comes out of the ground next to the house with an anti-backflow valve at the top. Then it goes back into the ground. Just before the pipe goes into the ground, there is an automatic drain valve which I believe should only open once the water is shut off and the pressure decreases. I assume this is the supply for the entire system. This system has been working well for years, but a couple of days ago it stopped.
I tried using the electronic wall controller to run it manually to see what the problem was, but none of the zones produced water. But what does happen is when the zone is turned on, water starts to dribble out of the automatic drain, and then turns into a strong flow which continues until the zone is shut off. Nothing comes out of the sprinkler heads, although I can feel a vibration in the shutoff valve for the zone being tested so I believe the valves are opening as they should.
I am not aware of any shutoff valve on the supply side of the sprinkler system. At any rate the system has been running fine and has not been touched until the water stopped flowing recently.
This doesn’t make sense to me. I would have thought the pipe going thru the anti-backflow valve would always be at normal house water pressure, so I am not clear on why there is an automatic drain on it. I would think this would mean a valve on the supply before going into the anti-backflow valve. I am stumped.
Any of you plumbers or sprinkler guys out there have any ideas?
Replies
I've never seen a backflow preventer with an automatic drain. What kind is it, Watts, Febco, Toro?
Everything in your system should be "live" from it's connection in the house, through the backflow preventer, through the main line, all the way to the zone valves.
I'm going to guess that the parts inside your backflow preventer may be worn out (replacement kits are sold) and it is somehow not letting water past the backflow preventer.
What kind of zone valves do you have? Silver Bullets or Irritrol? On most of them if you twist the sollenoid (sp?) the valve will manually open. Some have a screw you turn to manually open the valve and others have a little toggle type switch too. Look around and see if you can manually open a zone valve. If you don't get water, it means that no water is leaving your backflow preventer to charge the mainline. That'll at least narrow it down to at or before the backflow preventer.
Don't go by the vibrations in the poly or PVC pipe out in the zone valves. You'd be surprised how far away in the system those vibrations could be originating from.
I don't think it is a Febco, if those are the large ones with a couple of small valves on it for draining. This is one I replaced a few years ago. Got it at HD. It is very simple. Just a large screw cap on the top for access to the nylon and rubber part that prevents the back flow. The automatic drain is just something the installer put in on the downstream side of the backflow valve. Every one of my zones has one at the far end of the line so the lines automatically drain. So no problem with freezing in the winter.
I'll look at the valves tonight to see if I can operate them manually. That is a good idea. I just did not not think of it.
Thanks.
"I don't think it is a Febco, if those are the large ones with a couple of small valves on it for draining."Actually Febco makes a whole series of valves.They vary from the 710/715 atmopheric vacuum breaker, which looks much like an old radiator valve to 805 double check assemble, to a simple inline device that looks like a union.http://jerman.com/backflowpreventers/index2.html
Mine looks like the third one from the left in that link you sent. Thanks.
First, I want to thank both of you for the assistance.
Second, I managed to get the sprinkler working again last night.
I went home to try out the manual feature on the individual valves. They did not have them. My house was built in 1982 and I suspect the system is nearly that old. The valves are labeled "Weather matic - Dallas, Texas". The backwash is an Orbit 1". I tested the system again and determined there is a single master valve that controls flow into the entire system. Apparently when you turn on a particular zone, both the master valve and zone valve open. Each time I turned it on, I could hear the pipes with the backwash valve gurgling and slowly filling up. When you turned it off the pipe to the backwash valve slowly drain out. I could defintely hear water flowing thru the master valve as well. So I opened the drains on several of the zone valves as I tested each one. The water pressure coming out of these was pretty feeble. It seemed like my pressure was just too low, so the small amount of water flowing into each zone was just flowing out of the underground automatic drains without coming out of the sprinkler heads. The water pressure in the house seemed OK, but I guess a sprinkler needs a lot more. I was stumped. As a last resort, I opened up the water meter and shut off the water flow. When I turned it back on, the flowmeter jumped to light speed and the sprinklers started working.
All I can think of is there was some kind of blockage sitting against the shutoff valve and by moving it I dislodged it. I wonder where it went to. Next I'll probably find out my shower no longer works!
So mystery solved.
Thanks again for you help.