Wyze Thermostat on 2 wire system

If you have a 2 wire thermostat, as many of us do,
Rc (or The) and W, you still need a C wire to power the thermostat.
I couldn’t find a solution anywhere.
I ordered this, link below, and if you have a receptacle (outlet) nearby, you can fish the wire through the wall ( to make it more presentable) and boom. Should be good to go. It supplies power via a transformer to the thermostat.

1 Like

I have the same issue, I have installed it, from my furnace controller I attached one wire to rh one to w, as was the old thermostat, then from the transformer one to c and one to Rc, it’s powers it up but during app install it goes all the way through then it says turn on hvac system which I don’t have. I’ve tried a million combos and nothing seems to work. That combination is the only one I found that would power it up. I was under the impressions Rc was for a cooling system Rh for heat. So my first attempt was Rh, W the the transformer to c and G, g being the blower. no power at all. only attaching to Rc was there power. I’m still scratching my head. I’ll be interested in your results


The transformer I purchased says one wire goes to C and the other to RC ( maybe try RH on the next try if that doesn’t work), it also says that it doesn’t matter which wire you use, it’s non polarized.

I skipped past the wiring in the app. It kept telling me I had it wrong.

I hooked the transformer to RC and C.
I hooked the old wires to RH and W.

Everything works great.


That was my first try and I could not get past the turn on hvac system. When you used the app and it found your thermostat what was your next move

Thank you


I have tried those combo’s but when it power up and it says to turn on hvac which I don’t have



I am sorry I can’t remember just what I did. I put in my wires and it told me I was not compatible. I just added a c wire. I then got to the screen that shows you are missing wires or have too many. I somehow ignored that and went to the next step.

I do have another one to install. I hope to get to it this evening. If you have not got it working I will post the steps and explanation.

My original thermostat only used 2 wires, R and W (this is only for heat, no AC). But the furnace had terminals for C, Y, G, R and W.

The App wouldn’t let me proceed when I only clicked on R and W because it doesn’t include the power to run the thermostat. The C wire (common) supplies the 24v needed. So if you have R and W but no C, click on all three R,W and C in the app to continue the installation because you will then add the C wire. You will either need to add the C wire with an external wall adapter or if you are lucky as I was there was an unused wire, I was able to connect it at the furnace terminal and then at the Thermostat.

Once you have indicated R,W and C in the APP it will tell you to label them as Rc, W1 and C. After connecting the C wire at the furnace or adding a wall adapter you can then connect the Rc, W1 and C to the new Wyze thermostat and you are all set!

1 Like

I wish you could post a pic of your finished wiring installation

Could really use a hand. So I just bought a 24 v AC transformer because my thermostat appears to have just 2 wires. One of those two goes to “W” but also looks like it is bridged to “G”

I’m assuming

R becomes Rc
W becomes W1
But I’ve got 2 wires coming from the transformer. One obviously goes to C but what about the other?

I plan to get another transformer for the thermostat so saved these notes from someone else’s post. BUT I haven’t done it myself yet.

Transformer to RC and C
Heat to Rh and W

1 Like

This is how mine was done, I had a two wire system, then I used a transformer,

This is how mine was done, I had a two wire system, then I used a transformer,

I used the two wires from my furnace which were red in white in my case, and then I added a 24 volt transformer in my case green and blue in photo. I selected a transformer that I added wires to so I could adjust wire length to meet where I was plugging into. Attach to appropriate connections as my photo shows on the Wyze thermostat

This is incorrect.
Connect the transformer wires to Rc and C
Connect your furnace wires to Rh and W1
Polarity doesn’t matter if you only have 2 wires.

G and W1 will never be connected together by the thermostat, so your furnace will not heat properly with the way you have it setup.

1 Like

From what I have seen and watched on you tube I believe you put the transformer wires on C and RC
Thermostat control wires on W and R. No jumpers used. Try and report results. I awaiting my Wyze thermostat and also only have 2 wires and I will also be adding a 24 volt source for power.

1 Like

I just installed two Wyze thermostats on my 2-wire heating system

Added two 24v transformers and everything is running fine. Connect the 2-wire transformer to C and RC and attach your thermostat wires to W and RH

1 Like

It’s been working fine and is the only combination that actually worked, g is for the fan from the furnace and w is from the furnace, rc and c are from the transformer. To me it seemed like it should have be rh, instead of rc, basically my two furnace wires went on the same terminals as the old thermostat and the transformer wires provided the power where they need to be to get it to work.