Smart thermostat with hydronic heating, 2 zones

wiseplant

Hi All, new homeowner here learning the ropes of hydronic heating. I am attempting to install an ecobee 4 smart thermostat with my 2-zone system controlled by Taco zone valves and am trying to deciper this wiring diagram. How do the zone valves on this image correlate to the three terminals on the Taco zone valve?

https://support.ecobee.com/hc/en-us/articles/234939667-ecobee3-lite-with-4-wire-hot-water-zone-valves



Thanks in advance

HVACNUT

3 terminals. You probably have the Taco 550 series zone valves. Here's a cut sheet. The Common wire in the Taco diagram that goes from the transformer to the #2 terminals on the zone vales also connects to the C terminals on the thermostats.

Ironman

A word of caution: hydronic systems have much slower response than forced air. Using a setback or smart thermostat can be very counterproductive to the way they operate and may actually save no energy while sacrificing comfort.

The best thing you can do is set it (the stat) and forget it.