C wire adapter

How does the c wire adapter work?

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If you don’t have a C-wire, you would connect the 4 wires coming from the thermostat into the adapter and connect the 5 adapter wires to the 4 wire terminals that the thermostat wires were connected to. Then you connect the 5th (C) to the C or common wire terminal.
@WyzeChuan, who’s the expert can give a better explanation.

What if you only have 2 wires coming out of the wall?

Welcome to the Wyze community!
Unfortunately, your system may not be compatible at this time.

Thanks. I hope this changes!


I too have an old analog thermostat with just a white and a red wire but want to get the Wyze thermostat.
Youtube is showing some options but I haven’t found one specific to getting the Wyze thermostat working. Here’s a link that shows how they get around it for another system. Might be able to find a similar adapter…or maybe Wyze will add an accessory option later? How to Upgrade to a Smart Thermostat without Changing the Wiring | Ask This Old House - YouTube

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I also have furnace with just a red and white wire. Will it be possible to use an external power supply. Would really like to replace my Nest thermostats with these.

I believe and external c wire adapter will work( you can find them on Amazon). However your nest thermostat works with just 2 wire? It must have battery power? Why do you want to replace your nest?

Thank you for the reply I figured I that was the way, I have two Nest thermostats that I got when they came first came out before Google bought Nest. I have no other Google products and would like to standardize my home on one or two brands.

I have a two wire system as well. My current “smart” thermostat lets me use a wall plug adapter wired into the thermostat.

Can I wire that into the Wyze thermostat instead?

Does this adapter wire into the “C” terminal? If so, it may work.

The plug has two wires. One goes into the c wire spot and then the other goes into a different spot but I can’t remember what it is.

Could you take a look?
Remember to turn off or disconnect the power first for safety!

I plan to try this. From what I have researched, this should work. It seems like Wyze uses 24 volts. All I’m missing is a “c” wire so it seems like an easy fix.

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Anyone got this working? I just bought two Wyze thermostats because my house has two furnaces and would really like to get this working.

Thanks a lot

Welcome to the Wyze community @lappiesja!
We’re you able to setup your thermostats in the app?
Please post photos of your control boards and old thermostat wires if you have any issues.

Mine arrives today. If I get it working, I’ll let you know.

I got mine up and running with the adapter. Just hook up to “C” and “Rc” and since it’s AC it doesn’t matter which wire goes to which spot. The only issue I had was the app saying I had unnecessary wires hooked up where I didn’t even have any wires connected. I was able to skip the wire detection and everything is working fine.

Change of results. It was working with the adapter, but the furnace was endlessly cycling on and off. I tried various connections, but never got it to work properly. It might be that my furnace requires the power and common to come from it’s circuit board. I ended up running a new 5-wire line from furnace to thermostat which seems to be working.

If you have heat only, and you use a 24v wall adapter, its leads go into Rc and C, and your thermostat wires go into Rh and W.