Hi - I have a CT50, and just purchased a Z-Wave USNAP module from Amazon.
The module is recognized by the CT50 (I see an r2 on the display now), but I have not been successful when trying to mate / pair with my SmartThings hub. I did some searching through this thread, and tried resetting the ST hub and thermostat. I also pulled power from the thermostat for a while before attempting to connect to Z-Wave. Nothing seemed to help yet. I have reconnected to my WiFi at least.
It appears that the Z-Wave module was only recognized in the left-side slot (facing the front), and I still have my WiFi module in the right-side slot. I am assuming that since there are two slots, that I can have both modules inserted and operational at the same time.
Is there something I am missing here?