The Economizer Availability RA-T Compare module compares the outdoor air temperature with the return air temperature to determine economizer availability. If the return air temperature is greater than the outdoor air temperature by the Temp Difference SP value and the outdoor air temperature is less than the Change Over Temperature minus the Change Over Differential, then the economizer is available. When the difference drops below this value by the Temp Difference Differential, the economizer is not available. If the outdoor air temperature rises above the Change Over Temperature, the economizer is not available.
You can view and modify the modules in this group’s logic; however, the Free Cooling Availability contained within this module that performs much of the module’s calculations cannot be viewed or modified.