While flooding the trenches today, I noticed I have one valve that in order to get water to flow, I have to turn it enough to get water to leak from the solenoid. Took the solenoid off and it appears clear, even ran some water thru it to flush it, but still the only way to get it to operate manually is to unscrew until water leaks. Any ideas? Should I take the top off and clean it out, or call the dealer and request a new one? Brand new system, new parts, etc. Other valves work as advertized, 1/4 turn and they are on.