So we just moved to a new home. I have 1 Red that’s got 28V on it, and a white, yellow, and green. When it’s on the wall I’m getting a message for ‘No AC Power’. I cannot find any information on it, and when I use the multimeter I am getting a good 28V between red and the others. Right now I have it plugged into RH (Had it on RC last week), I did ‘reconfigure’ the wiring and it detected properly. Can anyone help as to why I’m seeing this and how to fix it?
Thank You
In order to draw AC power to power the tstat on AC, you would need the C wire connected which completes the power circuit back at the handler.
Without a C wire you would be running the thermostat on battery.
Wire colors don’t necessarily identify their function, always go by what terminal that are connected to in the old Tstat or at the handler board, however its pretty universally accepted that Yellow is used for the Y, Green is G, and White is W. These are cooling, fan, and heat stages, respectively.
C would be a fifth wire, and you would measure roughly 24VAC between R and C.