Can't add CT101 to SmartThings v3 hub

I’m just getting started with SmartThings using a new V3 hub. I’ve added two GE dimmers with no issues, but I can’t seem to add a CT101 thermostat (purchased as an “Iris” device from Amazon).

I’ve read a lot of suggestions:

  • Make sure the “C” wire is connected. Done. Also tried using battery-only (just in case of dirty power), and battery + HVAC power. No luck.
  • Move the SmartThings hub close to the CT101. I moved the hub to various positions — getting as close to two inches away. Still no dice.
  • Run Z-Wave Exclusion first. Done. When I run Z-Wave Exclusion on the SmartThings v3 hub and reset the CT101 (to get it to chirp), I see “1 device removed” pop up on the SmartThings app. This indicates the CT101 radio is working and communicating with the Z-Wave radio in the SmartThings hub.
  • Factory reset the CT101. I tried long-pressing the home screen on the CT101, but all that happens is the firmware version appears (I think that’s what I’m looking at). Is there a different reset procedure to try?
  • Make sure to remove the CT101 from an existing network before pairing with SmartThings. Irrelevant, since this is a new CT101 that has never been paired before.

Are there any known compatibility issues with the CT101 and the SmartThings v3 hub? Someone on here mentioned buying a new v2 hub to get things working, but it’s not clear to me why my hub’s Z-Wave radio would be malfunctioning since it can talk to my GE light dimmers with no issue.

Any ideas? I’m pulling my hair out over this, and am about to just buy a stand-alone WiFi thermostat. All I’m looking for is smartphone control over my thermostat…

Are you using the new app or the old one?

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Is it finding any kind of z-wave device when pairing? The pairing process should be the same between the two apps, but it may be worth trying to add it with the classic app.

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@fightingmajor, thanks for the suggestion! I’m new to SmartThings, and didn’t even know there was an old app.

I installed the SmartThings Classic app, fired it up, logged in, clicked “Add Device” and my CT101 popped right up! Wow!

Thanks a ton for the weird suggestion. I hope it helps someone else in the future!

(Of course, this solution doesn’t really make any sense, since the Z-Wave pairing process is going to be executed in firmware on the SmartThings Hub. Having said that, I’m way too nervous to remove the device, open up the old app and try to re-add it, just to make sure my setup didn’t mysteriously change)

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Don’t even bother with the new app. You only need it to set up the V3. Do everything in the classic app.

I have been fighting getting this same thermostat paired with my v1 hub. I’ve also read every post on the matter, excluded device numerous times, factory reset (found two different methods), etc.

I am using Smart things Classic app…

What I see happen is when I go to add a new “thing” in the app, the go through the menus on the thermostat the thermostat will actually display “LINK” indicating it linked to something but smartthings app never finds it. This happens Everytime after I go through the process to exclude it, factory reset it, etc. Once I exlude it the “LINK” text will go away and the LEDS alternate flashing orange and green again.

I’ve tried with just batteries as well as connecting to AC with batteries still installed.

Any suggestions? What device handlers are people using? Can someone provide the zwave fingerprint for this? Thank you


I am trying to pair my old Iris CT101 Thermostat with the new 3rd generation Smartthings Hub.

I tried all recommended solutions that I found like resetting the CT101 to factory standard and Z-Wave Exclusion through the hub.

What I like to try is whether the problem might be with the new Smartthings App so I like to try the Classic App with the CT101. But I can not pair my new 3rd generation Hub with the old Classic App since I did not receive a code with the purchase of the new hub (codes have only been send out for the 2015 hubs)

How can I add my new generation 3 hub to the classic app? Is there a general code for those new hubs that I can enter? Or did I miss something in the first place and is there a possibility of pairing the CT101 with the 3rd Generation Hub through the new App?

Any suggestion and help is greatly appreciated.