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Specifications
PKG-PRC002-EN 97
Options
Self-Contained Options
Air Volume/Temperature Control
• Zone Temperature Control
This option includes a zone sensor,
microprocessor unit control module, a
microprocessor compressor controller,
and a unit-mounted human interface
panel. The unit operates at a design
airflow based on the fan and motor drive
selections.
• Supply Air Temperature Control
with Inlet Guide Vanes
This option controls supply air
temperature to the specified supply air
cooling setpoint by modulating the
economizer option and/or staging
mechanical cooling on and off as
required. Control components include a
discharge air microprocessor controller,
discharge air sensor, pressure sensor,
and inlet guide vanes. The
microprocessor controller coordinates
the economizer control and the cooling
stages with zone or outdoor air reset
capabilities and an adjustable control
band to fine-tune the control to specific
applications. The inlet guide vanes (IGV)
operate with the self-contained unit to
control duct static pressure. The IGV
option includes vanes and static pressure
controls.
• Supply Air Temperature Control
With Variable Frequency Drive
This option controls the VAV self-
contained unit from the discharge air
temperature using a factory mounted
variable frequency drive (VFD). The VFD
safely varies the fan motor speed to allow
Inlet Guide Vanes
Side View of Unit with Waterside
Economizer with Removable Headers
the motor to meet the dynamic
requirements at the motor shaft and
meet the system static. Other control
components include a discharge air
microprocessor controller and discharge
air sensor. The microprocessor controller
coordinates the economizer control and
the stages of cooling with discharge air
temperature reset capabilities. Includes
factory installed and tested variable
frequency drive (VFD) to provide supply
fan motor speed modulation. The VFD
receives 0-10vdc signal from the unit
microprocessor based upon supply static
pressure and causes the drive to
accelerate or decelerate as required to
maintain the supply static pressure
setpoint.
Supply Air Temperature Control With
Variable Frequency Drive with Bypass
Manual bypass control provides full
nominal airflow and zone temperature
control in the event of a drive failure. The
VFD with bypass is factory mounted
completely wired and tested. A motor
overload relay and fuses are provided to
properly size motor protection during
both drive and bypass modes.
Waterside Economizer
The waterside economizer takes
advantage of cooling tower water to
either pre-cool the entering air to aid the
mechanical cooling process or, provides
total system cooling if the water
temperature is low enough. Waterside
economizing enables when the unit’s
entering water temperature is below the
unit’s entering mixed air temperature by
a minimum of 4 F plus the economizer’s
approach temperature. The approach
temperature default is 4 F and is
adjustable from 0 to 9 F. Waterside
economizing disables when the unit’s
entering water temperature is not below
the unit’s entering mixed air temperature
by at least the water economizer
approach temperature. The economizer
acts as the first stage of cooling. If the
economizer is unable to maintain the
supply air setpoint, the unit control
module brings on compressors as
required to meet the setpoint.
The waterside economizer includes a coil,
modulating valves, controls, and piping
with cleanouts. All components are
factory installed in the unit cabinet. The
coil construction is ½-inch (13mm) OD
seamless copper tubes expanded into
aluminum fins. The evaporator and
economizer coils share a common sloped
(IAQ) drain pan. Drain pan options are
either galvanized or stainless steel and
insulated and internally trapped.
The waterside economizer coil options
have either two or four rows with no
more than 12 fins per inch. The tubes are
arranged in a staggered pattern to
maximize heat transfer. The coil has
round copper supply and return headers
with removable cleanout and vent plugs.
The optional mechanically cleanable
economizer has removable cast iron
headers to allow easy mechanical
cleaning of the tubes. The waterside
working pressure is rated for 400 psig
(2758 kPa).