We had a sprinkler zone that did not send much water to sprinkler heads. Checked the spring on the solenoid. We took off the top of the valve and rinsed gasket and parts below – put back together. The zone then worked. However I then noticed that the valve that does not shut off completely – water meter shows usage. I turn off water as it comes from the house.We then replaced the solenoid, the zone would not turn on. When back to the old solenoid. I switched wires at the timer and valve, it started, but when the cycle was through there still was water going through the system. Put wires back to their original locations.Space is crowded and looks tricky to replace valve. Would like advice on that for next year. However my main concern is when we shut down for the winter. We manually run each of the 8 stations and blow out the water. Will the bad valve cause a problem?
If there's water going through the valve when it's in the off state, the valve seat or seal must be worn or damaged. If it's the valve seat, you'll likely have to replace the valve. When you say manually run each [station] and blow out the water, are you using compressed air? Otherwise, it's not clear how running water would blow out the water. In any case, if the valve in question opens, it should allow for your blowing out process, and if the water is shut off completely at the valve, no water should get in to refill the pipes.
You didn't mention who manufactured the valve. Sounds like you have a small stone caught between the valve body and the diaphragm. Diaphragms don't open that much and a large enough piece of debris can get caught. Also some valves are manufactured with a small tick screen that is inserted into the diaphragm itself. If it comes out then there will be a small hole in the diaphragm, causing leakage. Take the entire top off of the valve body and inspect the diaphragm. Be careful of the spring in the top. If it was a stone, you will see an indentation in the diaphragm. Feel around the seating edge to see if it is damaged. If all is OK, just put it back together, if not, take the diaphragm to a sprinkler place and get a new one.
we had the same problem last week. the valve was leaking allowing water to seep through. luckily it is a current valve and all the man did was replace the top part and that solved the problem. 75 bucks and he also checked out the entire system for proper operation.
Do you measure this 100 psi ahead of the antisiphon valve, or after it? I think you are measuring it after, and suspect the flow regulator on the antisiphon valve is not fully open. You could try adjusting it. It's also possible there is an obstruction in the piping somewhere. Any chance there is dirt in the sprinklers themselves? Also you could close down each sprinkler on a zone and see if the pressure comes up. If it does, there is no major leak. Any chance there is dirt in the spprinklers themselves?
