New Zone Switching Relay

BigEHead

My old Argo 3-zone switching relay died. I have 3 zone valves on one circulator pump, and 2 other circulator pumps for a total of 5 zones. I got a Taco 3-zone switching relay and wired everything the same as it was on the Argo. One of the honey well 4 wire zone valves was wired to the 24v transformer on the relay prior to changing the thermostat to a Nest. This zone valve motor isn't turning when heat is called from the Nest. When I manually click the end switch, the relay kicks in and the boiler turns on so I know it's the wiring to the motor from the thermostat. Anyone know why only this thermostat might have been wired to the onboard 24v and why it might not be working now? When I leave it wired to the 24v, the motor feels like it's powered but the valve won't move even manually. when i remove it from the 24v, i can at least open the valve manually. Thanks!

HVACNUT

All 3 of the zone valves and the Nest should be powered by a separate 40va transformer. Only the end switch wires should go to R-W on the SR503 to power the circulator for the zone valves. 

BigEHead

One zone valve was definitely connected to the 24VAC/COM on the Argo. Any idea why that is needed then? Right now the thermostat calls for heat but the zone valve motor won't turn either way right now (connected to 24VAC or not).

HVACNUT

What powers the other 2 zone valves?
Without knowing exactly how everything is wired, it's hard to offer a solution.

BigEHead

Thanks HVACNUT. I hard wired the zone valve to the 24VAC onboard and it worked. I then reconnected the 2 thermostat wires and it works. I think the common wire and the 24V wire were put on backwards. It's working now. Strange that I have 2 zone valves that are powered elsewhere but this 1 zone valve is powered by the switching relay. Thanks again.