At the Zone level of the Building Tree, a Zone Terminal box has been input as well as the Heating and Cooling Airflow values, and the Minimum CFM Ratio for the Zone Terminal Box. The Minimum turndown for this zone is lower than what is needed to provide the minimum code required ventilation for the zone. The minimum turndown airflow rate is equal to the Cooling Airflow times the Minimum CFM Ratio input for the Zone Terminal Box.
At the Zone level of the Building Tree, in the Mechanical tab, compare the Cooling Airflow input and the Minimum CFM Ratio to the code required airflow reported in this message. Note that while you may have chosen to input lower ventilation rates in the Room Occupancy tab, the code minimum specified by the CEC in the CBECC ACM manual tables will always be used as the minimum so you cannot go below this number.
Note that if you have checked the box for Demand Control Ventilation (DCV) your terminal box is allowed to turndown the airflow to 0.15 cfm/sqft and thus the minimum ventilation rate will be reduced in this case.
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