Air in irrigation System
I have been experiencing air in my 4 zone irrigation system. When I turn on
any zone the pressure at the sprinkler heads is barely enough to make them rise, and I hear air hissing through the selected zone valve. If I open the manual activation screw on the valve, air comes out for a little bit then the corresponding head gets full pressure. If I close the screw the hissing sound returns and pressure decreases. I am on the county water supply and since it is affecting all four zones my thought was the anti-siphon/back pressure valve maybe letting in air, I replaced and there was no improvement. There are no apparent leaks, cracks or water coming out anywhere around the valves. Any thoughts would be greatly appreciated.