I have an old Nelson system (probably from the late 1980s or early 90s that I am systematically updating piece by piece. The controller valve seems to be shot for a couple of my sections and I cannot find any Nelson parts to match it. I have seen the Hunter SRV-101 that looks just like my valves. Anyone know if the Hunter will work on this system? Would love to find a part so that I don't have to change out the whole thing. Thanks!