Desert Aire Aura QS, Installation And Operation Manual

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The unit will modulate the exhaust and supply air variable speed drives, open the
return air damper, and modulate the outdoor air damper. Check the pressure drop
according to the airflow label on the side of the unit. It is possible if the static
pressures are higher than specified that the flow rate may be lower. Check the
VFD speed. Units will leave the factory with a maximum VFD speed of 65 Hz. This
can be increased to 75 Hz maximum , subject to the current draw limitations of the
fan motor. Review the settings in the VFD drive to increase the speed.
3.3.4.5.3 Occupied Mode Maximum Outdoor Air (TotalAire™)
Place the unit in occupied mode and create a high space CO
2
reading (greater
than 2000 PPM). An offset should be placed in the controller input to reduce the
indoor sensor reading. If the reading is supplied by the BMS network, it is
recommended that this reading be overridden at the BMS control.
Check the pressure drop according to the airflow label on the side of the unit.
It is possible if the static pressures are higher than specified that the flow rate
may be lower. Check the VFD speed. Units will leave the factory with a maximum
VFD speed of 65 Hz. This can be increased to 75 Hz maximum , subject to the
current draw limitations of the fan motor. Review the settings in the VFD drive to
increase the speed.
For VerticalAire™ Products
VerticalAire™ dehumidifiers may be equipped with a mixing box that allows the unit to operate with
recirculation air in the unoccupied mode and/or mixing of airstreams during occupied mode. Two
independent actuators allow positioning of the dampers to the appropriate settings. Airflow must be
balanced in all modes.
If option is equipped, first operate the unit in occupied mode and adjust the damper positions via the
controller display independently until the desired flow of the outdoor air and the return air is achieved.
Outside air and return air duct will need to be measured independently by traverse or similar method
if this includes mixing.
Operate the unit in unoccupied mode of operation. Typically the outdoor air damper will be set to 0%
open position. Adjust the recirculation damper position to meet the required flow rate according to
static pressure differential per the balance label or independent test and balance measurements. The
airflow should be in the static pressure differential range or /- 10% of the specified airflow.
Should the flow rate be too high or too low, note the static pressure in the mixing box and compare to
the value measured during the occupied mode. Duct static pressures that are significantly different
will affect airflow during the shifting of modes. Dampers or grille adjustments will be needed to create
similar static pressure drops in each mode. Evaluate the system and adjust the dampers accordingly.
Desert Aire - QS/QV Manual