Piston valve vs Diaphragm valve for urinal
My local church has a few urinals that periodically (2-3 times per year?, maybe more because sometimes problems are not reported to me) run without stopping. The solution has been to hit the top of the valve a few times to get it to stop.
I've had the local plumber look at it a few times. Each time, they just open the diaphragm valve and just clean it out. They say that if the tiny pinhole is blocked, water will not shut off.
The church is on town water and it's possible that we have some old pipes somewhere that is flaking (Church was built in 1962), I don't know. Since we're on septic, I would like to find a way to prevent the water from running.
I was thinking that we should replace the valve with a piston type that is designed for harsh water conditions. If I do this, will it make the urinal relatively maintenance free or do the piston valve have their own issues? I've asked my plumber about piston valves but I get the sense that he doesn't have much experience with them.
With a diaphragm based urinal, how often should one have to service/clean the diaphragm? Is this easy enough that a reasonably handy person can do himself?