Have a W-R 3 wire zone valve that supplies all the heated water to the 1150 sq. ft. main floor. It's connected through a Taco ZVC 406 and I just can't seen to wire it so that it opens and closes on call. This valve needs power to open and to close and the wiring diagrams were, I thought, difficult to understand. I contacted Taco Technical support and they sent me a wiring diagram that I have included so you guys to take a look and maybe you can advise me on how to. The valve is wired as the diagram shows, but I don't know if I need a jumper between output terminals 3 and 4 on the Taco or if the Priority Zone switch needs to be on or off? Now, with this wiring, if the thermostat calls for heat, everything works ok, but when the heat requirement is met, the thermostat opens the contact and the Taco does not close the valve nor does it cut the power to two circulators that I have wired to one of the end switches in the Taco. Now, though the thermostat is open and is not calling for heat, the W-R zone valve does not close and that will keep the pumps running and the heat on. Puzzling. The Taco guys don't work on the weekends, so maybe some of you have experience with this type of valve.
