First Alert ZCOMBO from Iris

I’ve recently come over from Iris, and have moved most of my items over to Smartthings, but the First Alert ZCOMBO Detectors are not working with my Smartthings. Below are all the things I have tried and the results. I have a Smartthings V3 Hub and have tried all these steps on both the new iphone App, as well as the Classic iphone App. I have two of these Detectors, and neither one will work. Other devices have been able to connect/ add, so it is not the detectors or the hub. These detectors were used up until recently on the Iris Hub, so they definitely work.

-I have the device right next to the hub while trying to add it.
-I tried adding devices via in Rooms & in the Hub on the ST App. Neither work.
-I tried adding devices using the Auto Detect and Manually by selecting the brand. Neither work.
-Each time I close the battery compartment while holding the Test Button, then release it after the detector beeps (almost right away). The green power light blinks for about 10 seconds, then the unit beeps a long beep, the light goes out, and Smartthings does not see the device even after I repeat this step over and over.
-I have tried to exclude the device in the Utilities. I close the battery compartment while holding the Test Button and the device does the same things as listed above (while trying to add the device). The Utility never sees the device to exclude it. I’ve tried this many times.
-I’ve closed the battery compartment while holding the Test Button for 10+ seconds to Factory Reset. I get a long beep. I then re-tried the above to add the device and nothing worked. I’ve tried this many times.
-I’ve left the batteries out for over a day to hope to reset the device. After doing that, I re-tried the above, and nothing worked.

Please help, as I’m getting quite frustrated.

This device is tricky. I have two of them. I’ve migrated hubs several times and this device always took multiple tries to exclude or pair.

I would continue to try excluding and pairing. Looking at the instructions that I have, it doesn’t appear that you have to hold the button down until you hear a beep. Try releasing it right after closing the drawer.

Hope that helps.