I have had an ADC T2000 thermostat for several years. I also have three Remote Temperature Sensors. I recently added another T2000 thermostat to the system because I’m having the upstairs and downstairs set up with their own HVAC zones. One of the temperature sensors indicates that it is paired to the original thermostat, whether it is selected for control or not, while the other two indicate that they are unpaired. I can control off of any of them though, through the original thermostat. With the new thermostat, I can only use the two unpaired RTSs for control. The third RTS shows up under “Occupied Remote Temperature Sensors,” and cannot be selected from the new thermostat, even though it is not selected for control under the original thermostat. How do I unpair it from the original thermostat?
Temperature sensors are paired to thermostats in two ways, one for general manual control, and then separately they can be selected for schedules. Usually the schedule link is the issue.
Instructions on how temperature sensors get linked to schedules is found here near the middle:
Are you able to control it as expected after checking the schedules?
I had looked previously, but I had only looked at the cooling schedule, not the heating one. I looked again and checked the heating schedule, and there it was. I removed it and now it can control either thermostat!