Hunter PGV valve not opening after cleaning
I have a PGV valves in my 6yr old system. This spring, upon start-up, several zones began to bleed past the valve. I first tried to pull off the solenoids and open the bleed screws to flush the valves, however, the problem persisted. I then pull the valves apart and cleaned the valve, but still had valve leakage. As a last resort, (lawn was drying up) I purchased new valves and pirated the diaphram from the new valves. Everything worked for short period, however, some additional dirt got into 2 of the valves, and I again took the valves apart and cleaned out a single grain of sand. When i reassembled the valves, the zones will not pressure up. All other zones work fine, But the two zones I recleaned, will not allow pressure through. They are in different valve boxes and on different wiring. One zone by using the bleed screw, I can get normal pressure. On the other zone, I get enough pressure to pop sprinklers up, but only enough to spray half their area.
Any ideas/suggestions?