So installing thermostats in my house we just bought. 3 units. 3 thermostats. Installed the first two no problem. Have a question about #3, which is upstairs.

The other two were both RH, G, C, Y and W and the one i have a question about has its yellow wire going into Y2 as opposed to Y which doesn't show as a "valid configuration" when I input it into the installation app. I click "next" and the app says "please select a valid configuration". Should I just put my yellow wire into "Y"?

Screen shots of my new thermostats, the current wiring on the old thermostat which I found, and the screenshot from the app.

Need to see what that yellow wire connects to on the other end but the Y2 terminal is for second stage cooling on a two stage unit. Assuming your system is a single stage the yellow wire should just go to Y, not Y2.

Section327Ag said:

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Need to see what that yellow wire connects to on the other end but the Y2 terminal is for second stage cooling on a two stage unit. Assuming your system is a single stage the yellow wire should just go to Y, not Y2.

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Let me see if I can figure out if it's a two stage system. There's 3 units so I'll see which one connects to this system. I'll be out of town a couple of days and see.