As of last Wednesday my sprinklers did not work. After a lengthy investigation (pump start, breakers, wiring, timers, etc) I came to the conclussion that my 17 year old well pump had died. We replaced the pump with the same size as the previous one and water flowed. My problem is that stations 1 and 2 have a very low water pressure while 3 and 4 have the same pressure as before. We thought that the valves to these two stations maybe clogged but we arent sure. Any ideas or suggestions?
It's very possible that scale, rust, etc., came loose during the installation of the new pump and is causing a problem with the zone valves on your irrigation system.
Most valves have either a "jar top" that unthreads to remove the top, or screws that hold the top on. Inside, you'll find a spring and a diaphragm. Sometimes scale will get into this diaphragm, and won't allow it to function properly. Pay attention to the spring when you remove the top and be sure to put it back just the way it came out. The diaphragm will probably stick to the bottom half of the valve. Peel up one side of it, and it will come loose so you can clean it.
Last, make sure you reinstall the lid in the same position that you found it. There's a tiny hole that the solenoid fits over.