In order to utilize the "rear vertical" or "rear horizontal" discharge, the upper fan module must be
rotated.
1. Disconnect power wiring at motor terminal box.
WARNING
DISCONNECT AND LOCK OUT POWER WHEN SERVICING UNIT. FAILURE TO DO SO MAY RESULT IN
PERSONAL INJURY OR DEATH DUE TO ELECTRICAL SHOCK.
2. Remove corner connecting brackets which secure the blower module to the lower evaporator
unit.
3. Carefully lift the blower module and rotate 180°. Reposition the blower module on top of the
evaporator/compressor unit. Reinstall the corner connecting brackets.
Connect new power wire leads from the evaporator motor contactor in the electrical box to the
motor terminal box. Ensure wires are routed clear of any moving components. Secure the wiring so
that it does not contact the evaporator coil.
Figure 27: Evaporator blower discharge conversion
Variable frequency drive (VFD)
Optional Variable Frequency Drive (VFD) controller for the evaporator fan, mounted in the corner
post of the evaporator module, is available on the 10–25 ton models. The VFD shall be approved for
plenum duty applications. There are two VFD applications that are available: Variable Air Volume
(VAV) supply pressure controlled and two discrete speeds.
VAV supply pressure control
Airflow modulation and static pressure control shall be achieved by increasing or decreasing output
from the VFD. The installer shall provide two pressure sensing tubes complete with static pressure
taps connected to the factory pressure transducer. Compressor staging remains controlled by a
C-Series Vertical (CSV) Water-Cooled Self-Contained Units, B Generation, R-410A Installation, Operation, and
Maintenance Manual
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