Greetings, I have an old controller board that only has three wires run to it, The W, G and R terminals. There are no Y or C. Can the Wyze thermostat be wired to work with this system? If so, what would the pinout look like.
I see that the W, G and R terminals are labeled on the upper left of the board, but where is the Bus Bar for the wires that insert from the existing thermostat?
You are going to need the C Adapter, but I’m not sure about how the Y wire on the C Adapter will connect at the board since the Y is connected at the Condensing Unit to the Thermostat.
So you have a picture of the old thermostat wiring?
Perhaps @speadie could take a look and comment.
Thanks for a fast response! There is no bus bar for the wires from the thermostat. The wires are terminated with a spade connector and then pushed on to the control board.
Cheers,
Craig
C is blue on the transformer and is connected to chassis ground. Need to see actual wiring at the furnace board to recommend wire hookup.
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Thank you so much for your time and attention. I will get a photo tomorrow and post it.
Cheers,
Craig
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Good morning. Here are the photos for the controller board. It appears to be wired according to the schematic that I uploaded first.
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I need to see where these wires go. They should be spliced into the thermostat wiring somewhere. can you take a picture of that?
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I traced them out of the furnace. There are connected via wire nuts to the same signal on the thermostat. R-R, G-G and W-W. If still needed I will get a photo after work. Thank you so much for your help!
Cheers,
Craig
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I’m mostly looking to see where the Y wire is, and if you have any unused wires running between the thermostat and the furnace. A picture would be very helpful. It would also be helpful to get a picture of the wiring at your current thermostat.
Speadie,
From my notes, the Y wire goes to the condenser with a white wire before the thermostat cable reaches the furnace. They split and go different directions. Life interfered tonight so I could not get a photo. I will upload tomorrow morning. Many thanks!
Cheers,
Craig
Speedie, I got the photos this morning. I am not sure who installed this system but it is a rat’s nest. I traced all the wires from the thermostat and created a schematic from my findings. This is how it is currently wired, Let me know if you need anything else. Thanks again!
Cheers,
Craig
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Using the same/similar color wires contained in your schematic… connect the c adapter at the splice point as follows:
Tell the wyze app that your old thermostat has the following wires: Y, Rc, G, W
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Installed this morning and works like a champ! Many thanks for all your help.
Cheers,
Craig
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