This module is designed to generate the appropriate no airflow state for an air handler application and six other outputs to show the two supply fans statuses. The module monitors the two supply fans command and flow, and determines whether the current state should be Normal, Manual Reset Fault, Self Reset Fault, or Low Flow. This module is implemented as a control activity. The following state diagram shows how each fan’s airflow state is determined. The results of these determinations go through OR and AND functions to produce the outputs of the module.
Figure 1. Dual Fan No Airflow Sequencing Logic
You can view and modify the modules in this group’s logic.