I have a 3rd valve to allow me to pull antifreeze into the system instead of water, and two at the hot water tank (inlet and outlet).
Joe
We had one like that also. Maybe that is why ours didn't let the water through. The antifreeze one would stop the water from entering the pump if it was set wrong. Now we just unhook the inlet line and hook an extra piece of tubing onto the pump to put antifreeze into the lines. I liked the other way better but I can't find the kits any more locally.