Anyone got any ideas why an upstairs second zone will be running with full heat even when heat is off in zone? Seems like airflow from first floor zone is restricted and second zone is stuck open.

I run into this every now and then with Intellizone - a damper seems to get out of position. Cycle power to the entire system or simply take all thermostats to "system off" "fan auto", wait 10 minutes and then resume desired system operation.

If that fails, check damper positioners for freedom of movement - Belimo 24 series actuators have an oblong rectangular black plastic button that unlocks the damper shaft from the motor - depress it and check damper shaft rotation for ease of movement and ability to freely rotate 1/4 turn (90* degrees)