Got my CT100 installed, followed 2gig’s instructions for pairing, and judging by the display on the thermostat it went without a hitch, but when I try to add the device in ST, it just searches and searches, apparently til the end of time. Ideas?
Hey Jerry. I had the same problem with my CT100. I bought mine on Amazon through one of their warehouse deals, so I got a great deal but it also means that it has been used before. Because of this, the previous owner synced the CT100 to their z-wave hub but never un-synced it, which made it impossible (regardless of doing a hard reset of the thermostat) to sync it to a new hub. I returned this used CT100 to Amazon and reordered a brand new unused one (never been synced before). It worked/synced to my ST hub almost immediately. I don’t know if your CT100 is refurbished or previously used, but that may be what is happening. I hope this helps! 
Thx, Joe. I ordered mine new, so that shouldn’t be the problem, although I’ve gotten “new” items before that weren’t.
In any event, I gave up on connecting it to ST. It was the final impetus that triggered me to buy a Z-Stick and Indigo software. My vision of home automation has always been centered on a computer as the primary control center, not a phone, and it became obvious to me that I’d have a hard time ever pulling that off with ST. Indigo with the Z-Stick is a dream.