www.DaikinApplied.com 75 IM 1287-6 • REBEL APPLIED ROOFTOP
Propeller Exhaust Fan Option
Economizer units may include propeller exhaust or centrifugal
return fan options. This section covers maintenance and
operating instructions for the propeller exhaust option.
Centrifugal return fan construction, maintenance and operation
is similar to supply fans and covered in other sections of this
manual.
Figure 146: Fan Rotation
Figure 147: Three Fans with Bottom Return
Fan Prestarting Checks
Check all fasteners and set screws for tightness. This is
especially important for bearing set screws.
The propeller should rotate freely and not rub on the fan
panel venturi. Rotation direction of the propeller should be
checked by momentarily turning the unit on. Rotation should
be in the same direction as the rotation decal axed to the
unit or as shown in Figure 146 on page 75. For three-
phase installations, fan rotation can be reversed by simply
interchanging any two of the three electrical leads.
Fan Maintenance
Once the fan is put into operation, set up a periodic
maintenance program to preserve the reliability and
performance of the fan. Items to include in this program are:
• Bearings
• Fasteners
• Setscrews
• Lubrication
• Removal of Dust/Dirt
Damper Counterbalance Adjustment
The following instructions should be followed when attempting
to maximize the counterbalance eect on the dampers. Be
aware that when the balance setting is highly sensitive, friction
wear and contamination will have an adverse eect to the
operation of the damper. The sensitivity of the counterbalance
should only be set to meet the application requirements. The
damper must be mounted square and plumb and operate freely
before any weight adjustments are performed.
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