Wyze thermostat with zone valves in a hot-water baseboard heat system

Hi there. I think this is a super common situation that I haven’t seen addressed in the video.

I’d like clarification on multi-zone, hot-water baseboard radiator heating. (Note, I’m not talking “in-floor” radiant heating.) These systems use zone valves to control hot water flow to each part of the house. Each zone has its own thermostat connected to its own valve.

It would be helpful to have the instructions or tutorial demonstrate how to make this connection. It seems all the wires needed, including access to the common, would be present and available to wire in. Since the common would be there to power the valve itself. Shouldn’t it work?


I have exactly the same issue. I hope someone with tech knowledge can help us out! Thanks

Well I’ve got two thermostats on the way so I’ll be figuring it out one way or another. My system only uses 2 wires to the thermostat and has spare unused wires I can run the common through. Each of the existing thermostat wires attach directly to their respective valve boxes.

Really I think just a matter of matching up the correct wires on the valve and identifying the common which must be at the valve too. There’s a wiring diagram on each valve.

(Interestingly, the wires at the valves are connected with wire nuts, which the video warns us means it must be a line voltage system. Of course that’s not true. I think. Seems that would scare people off from this application.)

Maybe I can get a deal as a beta test installer for us simple Northern folk with old-fashioned furnace-driven hydronic heating systems and no A/C.

I LOVE this heating system! 3 zones, quiet, and heated ceramic floors in baths!
I don’t have extra strands of wire for common. Bummer. Pulling wire thru two levels is daunting. Good luck with the install.

There are adapters to provide C wire functionality available without fishing wire. I have a boiler system with the same 2 wire setup. My guess is that running one to the main Tstat will suffice since you say the wires run to each Zone stat from it, if I understand correctly?? If so those wires should be able to carry the C wire out.


Word of Caution, which you probably already know. Test the wire nut connections for voltage before messing with them. That can be very dangerous!

And I understand that comment. I live in the sunny South and hydronic heat is almost unknown here. Finding parts and/or knowledgeable techs is really difficult!

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Thanks for pitching in. I have three independent zones. 2 wires to each of 3 thermostats. No communication among thermostats, as best I can tell. Lowest level zone won’t require smart tstat, but upper two levels would benefit. Will explore wiring later today or tomorrow. Will keep you posted…


I agree. The zone valve motors are controlled, and also powered, by the 24 volt system so it should be a matter of pigtailing in to the common return where it connects to the valve wiring. As I’m learning, the zone valve itself is already wired to the boiler and that connection controls when the boiler circulator motor runs. So we shouldn’t have to mess around with that part at all. Or touch the boiler itself.

When we get those thermostats I’ll take pictures and post how it went.


Great-please post results and tips. I think it might benefit a lot of folks ( me included!)

@mike-mike-mike - any update on your install?

Haven’t received them yet - should be this week.

@pipan I’ve got the same setup you’ve described. I’m eager to learn what you came up with. I have a Wyze tstat with C-wire adapter waiting to be installed.

Unfortunately, the previous owners of our new house created a spaghetti situation.

The Red/Yellow wire pairs coming out of the valves are all spliced together with caps, and some of them are connected to the red/white two-wire (brown) leading up to the individual Tstats (these feed four baseboard zones in an addition on our home that has office rental units)

I was able to figure this out on my hydronic setup. The boiler has a 24VAC transformer installed at its electrical hookup to power all of the zone valves. This transformer has current capacity (so far) for 5 zone valves and 2 Wyze thermostats.

The transformer has R (hot) and C (common) posts. Follow the C wire to your first zone valve. This is where you’ll want to connect the C wire from a thermostat wire bundle that carries at least 3 wires. Follow the main C wire from one zone valve to another, and splice/nut in a C wire to each thermostat at each respective zone valve.

I’ll try to send pics in a bit. It worked well for me. Good luck!

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Nice!! Thank you.

What’s the current draw by the thermostats?

My thermostats were mailed in December but delivery is pushed back to late January right now.

I followed the green wire from the C “neg” post to each valve in series, adding a wire to the thermostat at each zone’s wire nut

I don’t know what the current draw is, but I bet it’s tiny.

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Hi, the thermostats arrived and I’m working on install. Wyze terminal Rc to R, W1 to W, and the C on the thermostat wired to the C terminal on the transformer inside the boiler.

Has anyone had the situation: the thermostat reboots and clicks every couple seconds, continuously, while trying to heat? Seems like a reboot to me, with “Wyze” logo reappearing each time.

yup i connected my common directly to this “NEG” / G terminal on my transformer I get power to the thermostat , but it seems to reboot every few seconds when it is calling for heat When it does no call for heat, it sits there quietly and powered on. I’ll try another thermostat location and zone next to rule out breaks in the wire But if you’ve seen this rebooting behavior, caused by the choice of wiring or which common I chose to use, love to hear it. I did switch the Rc and W wires in case that was the problem, but it wasn’t - Rc and W reversed just meant blank thermostat instead.

One odd thing - my boiler has two transformers - one built-in, and one that was obviously bolted on in the field. I wonder if choosing the correct transformer for my common matters also?

I used the transformer that powers the zone control valves. It was bolted onto the side of the boiler unit.

Yup that’s the one. I’ll let this question percolate a bit and try another zone to see if it has the same problem. Thanks!