Can’t Get Your CT101 Iris Smart Thermostat To Pair With SmartThings?

If you’ve been reading this blog, you know by now that I’m an Iris survivor. After making my choice for home automation systems that I would use to replace Iris, I’m working on getting everything set up. (I chose the Samsung SmartThings Home Monitoring Kit, btw). While most of my Iris devices were not compatible with my new home automation kit, one device I was very eager to dust back off was my Iris Smart Thermostat (Radio Thermostat CT101, a variant of this product). Unfortunately, I ran into some problems pairing my thermostat with my new SmartThings hub.

The SmartThings Home Monitoring Kit I purchased came with a SmartThings gen 2 hub. Everything I’d read said that I should be able to pair the CT101 Iris Smart Thermostat with the gen 2 SmartThings hub. It was definitely a frustrating experience to watch that MATE indication blink endlessly while SmartThings’ blue circle spun fruitlessly on my Android phone!

How I initially tried to get my CT101 Iris Smart Thermostat to pair with my SmartThings hub

I initially went through the complete installation procedure that I found in a PDF on Lowe’s website. The installation guide steps you through the complete process of setting up your thermostat to control your HVAC system.

After working through the installation procedure, I attempted to add the device in my SmartThings Classic app. As mentioned above, all I got was a lot of blue circle action with no device found.

It was at this point that I began, ever so slightly, to panic. I realized that I had never unpaired my thermostat from my previous Iris setup. Did I brick this thermostat? Is it because I have a 4-wire HVAC system with no C wire? What a lousy state of limbo I was in.

I got back into the installation PDF and looked through each page, hoping to have missed the magic instructions that would allow me to link my thermostat with my new SmartThings controller. I did find that once you finish the installation process, it refers you to the operations guide (also on the Lowe’s website):

A clip from the CT101 Iris Smart Thermostat installation guide that says: "Congratulations, you have successfully installed your unit. Please proceed to
the OPERATING Guide to initialize the CT101."
I felt like this guide was really on my side.

What an inspiring message! I figure: ok, I’ll find what I’m missing in the operations guide. So, I read through the operations guide and find the following heading:

“Communicating Thermostat”

Communicating thermostat! That’s exactly what I want! Unfortunately, though, I did not find any information on resetting my thermostat’s network settings or linking it to a new Z-Wave network. I only find some information on removaling the thermostat from an existing Iris setup. Yeah, that’s right, I said removaling:

An excerpt from the Iris Smart Thermostat operations guide that explains how to remove the thermostat from an Iris setup, but does not explain how to pair the thermostat with a new controller.
If only I’d removaled it from Iris previously

So, here I was, with my wireless thermostat only working as a wired thermostat. At this point, I had dismounted my CT101 from its wall plate and brought it immediately next to my SmartThings hub in the hope that it was simply too far away on the wall to pair.

No dice. So, time to hit the forums. I found some info on the SmartThings Community pages that helped me to piece together my CT101 Smart Thermostat puzzle.

Understanding the indication on your CT101 Iris Smart Thermostat menu

One clue for me was that the LINK indication was being shown beneath the radio icon in my CT101 menu. If you hit the MENU button, there is a little radio tower icon on the mid left of the screen:

The image above is copied from the operations guide. I’m not sure where the little “2” in the guide comes from. On my CT101, I only see a 1.

Here’s what this icon is telling you:

  • As far as I can tell, the LINK indication is shown when the CT101 thinks it’s set up on a Z-Wave network
  • The MATE indication flashes if the device is in pairing mode

On my thermostat, the LINK indication was being shown. Because I never unpaired this device from Iris, the smart thermostat was still set up for its previous network. From what I’d read in the forums, I believed I needed to first exclude my device from my SmartThings network before attempting to pair it.

Excluding a Z-Wave device from your SmartThings network

I’d read several SmartThings Community posts that led me to believe that, before I could pair my CT101 with SmartThings, I would need to first “exclude” my thermostat to snap it out of its previous network settings. One of the forum posts provided a link to Samsung’s guide for general Z-Wave device exclusion from your SmartThings network.

I followed the simple steps in that guide to get my SmartThings hub to try to exclude my thermostat. The steps (for the SmartThings Classic app) are, per the Samsung guide, as follows:

  • Tap the menu icon
  • Next, tap the hub (where it says “Hub is Online”)
  • Tap Z-Wave Utilities
  • Then, tap General Device Exclusion
  • Then click Remove

The SmartThings hub will now go into exclusion mode. The next step is to “follow manufacturer’s instructions” on your device to perform the exclusion process. Erm. I tried putting the smart thermostat in pairing mode (MENU -> MATE), but nothing happened. So, I went back to the Samsung forums.

How to put your CT101 Iris Smart Thermostat into exclusion mode

Here is what I had to do:

  • Take off the upper plastic cover on the smart thermostat that conceals the wire terminals
  • Reset the CT101 using the little switch to the left of the wire terminals
  • When it comes back up, hit MENU -> MATE -> MATE (hit MATE twice)

I still had my Iris Smart Thermostat immediately next to my SmartThings hub. After following the steps above, my thermostat pretty much immediately flashed its LED’s and the LINK indication disappeared.

Pairing your CT101 Iris Smart Thermostat with your Samsung SmartThings hub

Now, finally, the pieces were in place. With my thermostat still next to my gen 2 Smart Things hub, I went back into my SmartThings Classic app. I set the app to add a device and then hit MENU -> MATE on my CT101.

Still nothing! At this point, I reset my smart thermostat (using the switch next to the wire terminals) and then attempted to put it in pairing mode again by hitting MENU -> MATE.


If you are having trouble pairing your smart thermostat with your SmartThings hub, I hope that this process will help you to resolve your issue. If it doesn’t, please let me know in the comments below. I’d also love to hear from you if you’ve had to work through the same problem with a gen 1 or gen 3 hub – or if it’s any different on the iPhone app.

Thank you for reading!

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Here were some of the SmartThings Community posts that helped me to figure this out:

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  1. Skyler โ€“ Thanks for this post, man . . . saved me much frustration. I too am an IRIS orphan and finally decided to adopt SmartThings, in part because it promised to connect with the CT-101. I have the Hub V3 and your procedure worked exactly as you described for the Hub V2. I want to also reiterate your comment about locating the thermostat right next to the hub for the initial connection, which was the final piece of the puzzle for me. Thanks again. ~Walter

    1. Walter – No worries, sir, glad it helped. Thanks for letting me know that it works for the V3 hub. Sure is nice to have remote control of that thermostat, huh? ๐Ÿ™‚

      1. Yes, of all the components in my IRIS system, this is the one I did NOT want to replace. So, thanks again.

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