Thermostat R&W, G not connected

Attempting to update my old thermostats. I have a hot water baseboard system, heat only, no A/C. The old thermostats have two wires, R&W, with a green wire wrapped around but not connected. Can I use that Green wire as the C wire to hook this up?

The third terminal on the upper part of the zone relay should be common, connect the green wire there.

Then connect the green wire to C on the wyze.

Do this with the power off, or you might blow the fuses on the zone relay.


Thank you Speadie. Right before the switching relay in the picture above is this aquastat. It also has a green wire wrapped around and not hooked up. Do I need to hook this one up as well?

I also followed the line that enters this aquastat backwards to this junction box and see that the green wire in there is also not hooked up.

The aquastat shouldn’t need the green wire hooked up, just the connection between the zone control and the thermostat. You need an uninterrupted run between the C terminal on the wyze and the com terminal on the zone relay.
If the green thermostat wire is interrupted in those boxes, then it will need to be connected together, but the resolution on those images is too low for me to be able to see what’s going on inside them. Don’t connect the green wire to other terminals, or to the ground wire for the 120V wiring.

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