The Unoccupied Sequencing subgroup of modules determines the action of a unit when the zone temperature drops below the Unoccupied Heating Setpoint or rises above the Unoccupied Cooling Setpoint. The general sequence of operation is to cycle the unit and its heating or cooling devices on and off during unoccupied to keep the controlled temperature within the Unoccupied Heating and Cooling Setpoints. When the temperature goes outside the limits set by the Unoccupied Setpoints, the unit is typically started and the appropriate device (heating or cooling) operates at its limited max value. When the temperature returns within the limits, the unit continues to operate for a period of time and then turns off.
In some cases, the heating device is opened if the outdoor air temperature is low during the unoccupied mode.