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DN-Series Integrated Programmable Controls
DOAS
UNIT OPERATION
5.3.2 EA Flow Control Option
The controller will adjust the supply fan VFD or ECM command to maintain the EA flow rate at
a setpoint.
The EA flow rate setpoint is entered and adjusted from the unit controller display or provided by
the BMS. The minimum and maximum values for EA flow rate setpoint are unit dependent. An
adjustable PI loop will compare the measured EA flow to the airflow rate setpoint and adjust the
fan speed. If the measured EA flow rate varies from the desired airflow rate by more than 10%
(adjustable) for more than 60 seconds (adjustable) an EA flow rate alarm will be set to true. This
exhaust fan operation mode can be used to provide a constant EA flow rate as the unit filters
become loaded.
5.3.3 Supply Fan Command Tracking Control Option
The controller will adjust the exhaust fan VFD or ECM command to track the supply fan VFD or
ECM command.
The minimum (50%) and maximum (200%) tracking rates are adjustable. This exhaust fan
operation mode can be used to maintain proportional supply and exhaust fan commands as the
supply fan modulates.
