Just replaced a White Rogers digital thermostat with the 3M-50. I wired the 3M product the same way the WR product was installed and I had everything working including wifi within 20 minutes.
I noticed that there is an option to control the fan motor with the 3M-50 but my wiring setup does not have a line for the fan motor. Rather, there is a "ventelation" switch adjacent to the thermostat that turns on and off the furnace fan motor and the bathroom fan.
What I would like to do is tap he 24 volt line running to this ventelation switch and connect it to the G line on the 3M thermostat.
I traced the lines back to the furnace and discovered that the ventelation switch shares the red RH line with the furnace. The black line connects to a terminal on the furnace labeled "G".
This seems far too simple to me, should I simply connect the black line to the G terminal on the 3M-50?