Thermostat Setup - No Y or W wire on control board

Below is an explanation of my issue. My AC is requiring the installation of the C-Wire adapter when I go into the control board of the AC unit. I see the below wire diagram which I see XFMR-R, R, XMFR-C, C, G. My AC control panel has R (and a jumper wire to RC), W, Y, and G. My control board does not have W or Y. So I am not sure where I need to connect the W and Y if my control board does not have those. Also, I found my power label, and I see it reads 208/240V, but do not see anywhere that it says “high voltage” like the app says or none of the wires have any “wire nuts”. If my system is a high-voltage system, could I use the following external power source to power the Wyze unit? Amazon.com

G-Drive w/ pictures of wiring and diagrams - Wyze Thermostat - Google Drive

If any further information is needed please let me know.

Suggest you look behind current thermostat.
Take it off the wall and I’m guessing you’ll find a Blue (common) wire tucked inside the wall like mine was. If it is you’re all set assuming it’s connected at the furnace. All furnaces/AC’s are 220volts. Your diagram indicated a 24volt transformer for the thermostat.

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This is your air handler.
There should be another control section for heating and cooling.
All this board does is control the fan. Follow the wires marked R (red) and C (blue) off of this board and you should eventually come up to the thermostat wires and possibly a secondary control board.

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You are a genius, tucked there was the blue wire. So the blue wire would be my C wire?

Yes blue is your Common wire. As other poster indicated it will need to be connected at the furnace control board’s C terminal.

So I found the wire, and it is not connected to the board, but in the board, there is already a wire connected there. I tried to follow the wires to see if there was another board and did not find one. I added new pictures to the G-Drive, thank you for the help.

https://drive.google.com/drive/folders/1B1Q-dt6Q5X6ewVjAKAoJVJ6y8zbXEK8X?usp=sharing

Multiple wires can be connected to C. Just strip the blue thermostat wire and add it to the other wire that is connected to the blue C wire and wire-nut them all together.

Might also be a good time to vacuum out your blower fan. :slight_smile:

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You can safely have two wires connected to the C terminal. Just make certain the furnace breaker or switch is off first.:wink:

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@speadie thank you both! highly appreciate the help! and yes, did not notice how dirty my unit was lol Will update if things work. :wink:

Great success! It worked, no issues. Thank you @chris1952 and @speadie for the quick and accurate help!

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Happy I could help.

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