Application
IMPORTANT:
The VFD66 Series Condenser Fan
Speed Controls are intended to control equipment
under normal operating conditions. Where failure or
malfunction of a VFD66 control could lead to an
abnormal operating condition that could cause
personal injury or damage to the equipment or other
property, other devices (limit or safety controls), or
systems (alarm or supervisory) intended to warn of
or protect against failure or malfunction of the
VFD66 control must be incorporated into and
maintained as part of the control system.
The VFD66 control accepts input signals from a variety
of pressure transducers, temperature sensors, and
low-voltage controllers to provide continuous response
to changing condenser load conditions.
The VFD66 control allows the system to:
maintain optimum condenser head pressure in low
ambient temperature conditions
eliminate short-cycling in low ambient temperatures or
changing load conditions
match the condenser fan speed to the load on the
condenser, which increases the efficiency of the
refrigeration system. This can reduce electricity cost
and help maintain a constant evaporator temperature.
Terminal
Access
Cover
Terminal
Cover
Screw
Heat
Sink
7-1/2
(190)
7
(177)
3 conduit openings
7/8-in. (22 mm) actual size
1/2-in. trade size
1/4-in. (6 mm)
mounting screws,
4 places
6-1/4
(159)
4-3/4
(120)
4-5/8
(117)
7-1/4
(184)
Diagnostic
Light-Emitting
Diodes (LEDs)
Figure 2: VFD66 NEMA 1 Enclosure Dimensions
The VFD66 control can also:
stabilize the condenser head pressures, which helps
optimize compressor operation and can reduce wear
and extend compressor life
eliminate the condenser fan short-cycling, which can
reduce motor repair and replacement costs
stabilize evaporator temperatures, which can extend
refrigerated product life and provide more consistent
comfort cooling
Mounting
!
CAUTION: Risk of Property Damage.
The VFD66 control can generate and dissipate
significant heat. Mount the control on a metal,
concrete, or cinderblock mounting surface. Mounting
the VFD66 control on surfaces made of wood or
other heat-sensitive material may result in damage
to the mounting surface.
Observe the following the guidelines when mounting a
VFD66 control:
Mount the VFD66 control on a vertical surface with the
heat sink fins oriented vertically and the conduit holes
facing down.
Provide a minimum of 4 in. (102 mm) clearance
around the heat sink.
Ensure that output power wiring between the VFD66
control and the motor does not exceed 50 ft (15 m).
Mount the VFD66 control indoors, in a location
protected from explosive vapors, corrosive gas, water,
and dust.
Ambient air temperature and installation altitude affect
the maximum output rating of the VFD66 controls (see
De-Rating the VFD66 Control for
High Temperatures and High Altitudes).
2
VFD66 Series Condenser Fan Speed Controls Product/Technical Bulletin
