Question
I have a simple four zone 3/4" in-line sprinkler system.  The sprinklers have been working fine until recently.  There is not enough pressure to get sprinklers to pop up and water far enough out.  We flushed through all the lines and did get a bunch of rocks out but still didn't effect the pressure problem.  When we open the manual bleed the pressure works great and all the sprinklers work correctly.  We have adjusted the pressure valve on the top of the valve and doesn't effect the pressure at all.  We replaced the diaphragm and the silenoid and still no luck.  When we open the bleed water shoots out of it and you have to manually turn it off then.  We have gone to several different hardware/sprinkler stores and no one seems to know what's wrong.  Do you have any suggestions.  Our kids are playing on hard ground and straw and in arizona having grass is a definite luxury.  Thanks for you help.  Jennifer

Answer
Jennifer,
If you flushed the lines and got a lot of rock you may have rocks and debri at the connection going to the heads. It reduces down at the head to either 1/2" OR 3/4" and there would be the next place to look. also check and make sure the water is on all the way and that the valve that turns the system on and off is opening fully. With the heads running listen and see if you hear a hissing noise at the valve. I am asuming the on/off valve is not 3 feet in the ground. Jim