You can schedule to run your fan for a minimum duration per hour in order to maintain circulation in a space. If the minimum hourly fan runtime is not exceeded as part of normal HVAC operation, the fan turns on at the end of the hour for the length of time required to fulfill the minimum hourly run time. The fan runtime calculation includes runtime initiated when the Fan Mode is set to On and other overrides. The fan does not turn on if the fan runtime is already longer than the minimum hourly fan runtime. When you enabled the Scheduled Circulation Only When Occupied setting, the fan does not turn on at the end of the hour to fulfill the minimum runtime unless the occupancy state is set to Occupied.