I wanted to connect the humidifier so that it would use the humidity control of the thermostat but (I don't understand how that would tell the humidifier what RH% to max out at.)
At this point I'm just looking for the simplest way to get this humidifier working because our house is at 14% humidity.
The Orange U1 wire at stat connects to the red wire of this fresh air damper . The white wire of damper connects to a 20VA transformer in the furnace (yellow wire). The black wire at STAT U1 connects to the thicker blue thermostat wire (2nd pic)
Aprilaire 600M came with it's own 24 volt transformer if I need to use it.
Thanks in advance for any help these two solenoid wires are all that's keeping us from comfort!!