Installed a zone for drip, it worked fine for the first year (that I know!!) Now, it (valve) won't shut off. Starts out from manifold - 1" Baccara valve (rated down to .5 gpm) runs to drip area, into 25 psi pressure regulator, and into drip line. There is only about 18 1gph emitters. (.3 gpm) I can make the zone shut off by closing the valve regulator off, or opening the end of the drip line. So, I would like your input if my thinking is right. I am assuming that valve won't close because there is not enough "usage" and hence pressure differential across valve. So, since I didn't need any more emitters for plants, I installed a VAN head just outside the area, figuring that that will increase the gpm enough for valve to work. NOT Gutted the valve, flushed it, still don't work. I am guessing I need to install a valve that can tolerate a lower flow. Would you agree this with this logic? Thanks a bunch!