I'm having an issue with wiring my Weil McLain gas boiler. It was wired up fine and working for a single zone. I added (2) 4 wire zone valves in. So I now have 2 zones, a Taco zone valve controller(zvc-403), and two ecobee thermostats. And I have no idea how to wire it up.

I watched a video that showed me how to wire the valve controller. By wiring the circulator to the pump end switch and each of the thermostats to the proper zone and each zone valve to the proper zone on the board. That was pretty self-explanatory. But my question is: What happens to all the other connections on the boiler?? Like the water limiter and the gas wiring relays etc. I currently have a transformer relay with a lot of wiring connected to it - and no idea what to do with all those connections.

Do I just take the thermostat wires off the existing relay transformer and connect them in the controller and bring 120V to the controller to power it, and leave those connections powered with 120V to work completely on their own as long as it has power?

Or do I remove the thermostat wires from the existing relay transformer and bring the them to the controller, and remove the 120V power fro the existing relay transformer, and run the thermostat wires through the relay transformer as they were before? So no power in that relay transformer.

They completely left out what to do with all these other existing connections. I have some pictures of what my boiler looks like and the controller. Can anyone help with this? I have a decent idea of electrical work just never worked with HVAC and relays. enter image description hereenter image description hereenter image description here

  • I was a bit confused about what a "taco zone valve" was (a restaurant name "taco zone" with valves? a zone valve shaped like a taco?) until I Google'd to find that Taco is a brand. Capitalized brand names for clarity (except ecobee since they do the e e cummings thing) and fixed up a bunch of other spelling/grammar issues. Unfortunately, I have no experience with these types of valves, so I can't actually answer the question :-( – manassehkatz Oct 14 '18 at 14:12
  • This YouTube video, might be helpful. – Tester101 Oct 15 '18 at 11:11
  • It helped. I saw it before. I just wasnt sure how to signal to the boiler to turn on. But i will wire it as it says in the video. The thermostat and zone valves arent the issue for me. But im going to wire the pump end switch (XX) to where my thermostat wires originally were on the transformer relay. And it should send the signal to the boiler to turn on when the valves open or the tstats call for heat. And it should fire up just as it was before. THANK YOU TESTER – Kirk Oct 16 '18 at 0:47

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