Deleted device in HomeKit cannot be rediscovered

It might be a wifi issue. First your phone will need to be on the same network as the thermostat: 2.4 GHz band (not 5 GHz). If you prefer 5GHz for your phone, you can switch back to that after set up.

Try also rebooting your wifi router.

Thanks - Check - yes everything is on 2.4gHz together on the same network and we've rebooted with no joy. :-/

If your device is still set up in the manufacture's app you may need to use that to add it to HomeKit, or delete it from that app too before it can be added once again.

Thanks - It is up and running in the manufacturer's app. That actually took some doing so I'm a bit hesitant to delete it and start over, but might go there if nothing else works. At least it's an option though!

Interestingly the thermostat still works fine in their app. But when I use their UI to add it into HomeKit , all it does is bounce me over to HomeKit where the device no longer shows - as per this thread.

I made a little progress - but it's got me back to square one still saying "no response". I found some online instructions to delete the HomeKit settings in the thermostat - without doing a full hard reset! Good news.

But - when I dd this, and scan the QR code to add the unit back - th result is the same as I had originally. It shows up in HomeKit - with "No Response"! Not exactly progress but good to know I can recover something. Meanwhile it's happily running in the manufacturer's app. Guess I could settle for that - worst case scenario. But it's a challenge now so I'll probably keep tinkering with it. I'm going to be adding other HK items soon so need to learn it anyway I guess.

PERFORMING A HOMEKIT RESET (Honeywell T10+ Pro)

1. Press the Menu Icon

2. Scroll down to “Thermostat Information

3. Record the “Date Code”

4. Press the “back” arrow, then scroll down to “Installer Options”

5. Enter the Date Code when prompted to “Enter your password”

6. Select “Reset”

7. Select “HomeKit”