No control board for C-wire adapter Wyze thermostat

I have no circuit board or control board in my HVAC system. The wires that go to my thermostat is blue (Y), green (G), white (L), and red - R. I do not suspect my HVAC is high voltage system. Any help much appreciated!!

Electric resistive heat?

Then L is W

You actually have a board, but it is under that enclosure frame in front. You’ll need to remove the hex head screws that are hiding under the wires running across the top of the frame in order to access it. It’s hiding the terminals and transformer wires, so with it in place, I can’t tell you where to put the common.

I’m not sure if I have electric resistive heat. I’m not familiar with it. I did a bit googling that ERH is common if you live in a state that do no require a lot of using heater as I live in Florida. I could be wrong.

I saw that board and I didn’t know that is actually the control board. I will remove it later or tomorrow as I’m outside right now until later in the evening.


I see the R,C,G,W1 and W2 connection cables after removing the enclosure frame. See the pictures attached. I also see the white color cable (L) that connects to my thermostat is wired to the next part on (w1) in the picture. Any suggestion and help to wire the cables to the c-wire adapter much appreciated!

So my furnace is not high voltage system and compatible to Wyze thermostat, correct?


Your furnace uses 24v logic. Look at the label on the other side of the transformer.
Find the other end of the brown wire that comes off this connector. It is C.

If you have an extra wire behind your thermostat, find out what color it is and then connect it to C.
You might have trouble using the C adapter here because I do not see a Y wire anywhere.

I do not see I have extra wire behind the thermostat (last picture). The brown wire goes to the red wire connector with red color cable in the first picture (blue highlight), then it goes up (third picture) all the way to the top and it goes to the bottom behind the wall in the second picture and I believe it goes to the thermostat.

The brown wire has red, white, green, and blue.

The second brown connect to the blue, and yellow wire connector in the first picture, then it go all the way to the R, G, W1, and W2.

This is the diagram


Can I see the wirenut that is attached to the blue and white striped wire?
In fact, I really need to see all the wires that go into each of those wire nuts that are all ziptied together in order to tell you how to properly hook up your wyze adapter.

Here is the picture that all the cables ziptied together.

Ok, Now we’re getting somewhere.
I’ve labeled the wire nuts in your image with their letters.

The red thermostat wire going to C and the White thermostat wire going to Y are going to your AC Compressor.

So, with that diagram, here are the instructions for wiring your wyze adapter:

Attach the C lead of the adapter to the wire nut labeled C. Do not remove any wires from this connection.

Attach the G lead of the adapter to the wire nut labeled G. Remove the green thermostat wire and place it in the wyze’s G Adapter terminal .

Attach the R lead of the adapter to the wire nut labeled R. Remove the red thermostat wire and place it in the wyze’s R Adapter terminal .

Attach the W lead of the adapter to the wire nut labeled W. Remove the white thermostat wire and place it in the wyze’s W Adapter terminal .

Attach the Y lead of the adapter to the wire nut labeled Y. Remove the blue thermostat wire and place it in the wyze’s Y Adapter terminal .

At your thermostat, connect the blue wire to Y1, the red wire to Rc, the white wire to W1, and the green wire to C.
Tell the app you have R, G Y, W.

I was able to implement the wire per your instruction. Now the wyze thermostat is working.

During the setup, I picked W1 uses electric and W1 Heat control uses “forced air”

Thank you soooo much and I’m really appreciated your assistance.

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