Desert Aire Aura QS, Installation And Operation Manual

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the return air duct flow rate after every adjustment, and continue adjusting until the
ratio of flows is correct. In cases where the return air static pressure is high, the
recirculation damper may be fully open without the desired ratio being attained. In this
case, keep the recirculation damper fully open and adjust the outside air damper to a
more closed position. Check the return air duct flow rate after every adjustment, and
continue adjusting until the ratio of flows is correct. Verify the blower has maintained
the supply airflow.
Switch to unoccupied mode and verify that the outside air damper closed completely,
the recirculation damper opened completely, and the supply airflow is maintained at
steady state (this may take a few moments as the blower control loop stabilizes).
3.3.4.1 For Units with External Enthalpy Wheel (Aura™)
In occupied mode, use a magnehelic or inclined manometer to measure the
air pressure drop of the exhaust blower. Increase the controller signal up or
down until the exhaust air pressure drop matches the pressure drop indicated
on the nameplate. Then complete the balancing from section 3.3.4.
Check the pressure drop of the exhaust blower after balancing the dampers
and adjust the exhaust blower signal as necessary. Verify the exhaust blower
adjustment did not alter supply air operation. If the adjustment has altered
supply air operation, repeat the supply air balancing and then the exhaust air
adjustment until all airstreams are within specifications. Verify that, in
unoccupied mode, the exhaust blower shuts down.
3.3.4.2 For Units with CO
2
Control (Aura™)
Dehumidifiers designed for CO
2
control can have mixed airflow composed of
a range from 100% outside air to a minimum ratio of outside air dictated by
the design. The outside air damper, recirculation damper, supply blower, and
exhaust blower are all controlled by PID loops. To balance, set the CO
2
set point to 200 ppm and verify the pressure drop across the supply side of
the wheel is at a minimum indicated on the nameplate. Also, verify the supply
blower is maintaining the design airflow.
Adjust the CO
2
set point to 2000 ppm and verify the outside air damper opens
fully, the recirculation damper closes fully, and the supply blower still maintains
the design airflow.
For TotalAire™ Products
TotalAire™ dehumidifiers may be equipped with a recirculation damper that allows for
mixing of outdoor air and return air. A separate damper and actuator are installed
between the return air and outside air streams prior to the exhaust air entering the
enthalpy wheel. Controls may be set to allow for a mixed air condition during
occupancy and/or full recirculation air during unoccupied mode. Airflow must be
balanced in both modes.
Desert Aire - QS/QV Manual