Desert Aire SelectAire Plus SP Series, Installation And Operation Manual

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Desert Aire - SP Manual
CFM should match the mode OA CFM Stpt displayed. Note that some fluctuation is to be
expected, particularly if heavy winds or wind gusts are directed towards the OA intake at
that time, but on average the value will be close to the setpoint.
3. Note the OA damper position. Ensure this damper is not commanded to the minimum or
maximum position. If it is, review to ensure that damper is physically moving and review
the static pressure in the OA duct if this is an indoor unit.
4. If desired, measure the outdoor air flow rates independently through the use of direct
measurement device such as hood, velgrid, or anemometer.
5. Repeat the procedure for the other outdoor air modes as desired by scrolling through the
screens and changing the override for each mode. The modes available are dependent on
the types requested at the time of unit order. These may include “Event”, “Max. OA”, and
“Purge”. Note that controller power will need to be removed after completing “Purge” mode
as the post-purge operation will lock out outdoor air operation for 30 minutes after purge.
The flow rate for each mode can be adjusted in the field through the controller, but it should be noted
that there may be physical limitations to the amount of flow that can be introduced. Also, note that
very low return air static pressures may limit the amount of outdoor air that can be introduced. The
very low return air static pressures are encountered and there is a desire for high outdoor air flow
rates, a restriction or damper may need to be placed in the return air duct. Consult the factory for
further recommendations.
Exhaust Airflow Setup
The unit exhaust airflow rate should be confirmed for each mode that was specified at the time of
order to ensure that the duct system static pressure encountered allow for proper flow and zone
negative pressurization. Ensure all doors and windows to adjacent spaces or outdoors are closed
before balancing the exhaust air.
1. Review the exhaust air flow rates for each mode programmed into the controller display
under SERVICE MENU AIRFLOW SETTINGS AIRFLOW SETUP MAX EXH.
FLOW RATE. These settings have been factory pre-set to the airflow indicated at the time
of unit order. It should be noted that these flow rates act as maximum flow rates for each
mode of operation. The controls attempt to achieve a negative zone pressure.
2. Use the controller display under SERVICE MENU AIRFLOW SETTINGS AIRFLOW
SETUP EXHAUST AIRFLOW SETUP to set the Set Unit Override to the first mode to
be tested. Set Exhaust Mode to “Cool”. Ensure the “Ex Max” is set to 100%. Unit will open
the Cool Air Exhaust Damper downstream of the evaporator coil. Units specified with high
amounts of exhaust air may also open the exhaust damper upstream of the coil in this
mode.
3. Allow unit to stabilize. Fan speed, damper positions, and zone pressure should be
relatively constant.
4. Review the fan speed. A speed of 90% or greater in any mode may indicate high exhaust
duct static pressures or static pressure set point that is too high. Correct any issues with
exhaust duct routing, size, or total length.
5. Review the zone static pressure. The recommended zone pressure is -0.050” W.C. for