I'm at a loss. I have four anti siphon valves and three of the four work. The fourth I have replaced every part including replacing the entire valve unit. After turning off the valve water gushes out from the cap. It slows but continually leaks. When I take the cap off and siphon some water out, the water levels continues to rise. As stated I have replaced the diaphragm, the solenoid and the washer and cap. What else could it be? Thanks.
