262292-YTG-C-0707
8
Unitary Products Group
FACTORY-INSTALLED OPTIONS
•
SINGLE INPUT ELECTRONIC ENTHALPY
ECONOMIZERS
- Includes a slide-in / plug-in damper
assembly with fully modulating spring-return motor
actuator capable of introducing up to 100% outdoor air
with nominal 1% leakage type dampers.
The enthalpy system contains one sensor that monitors
the outdoor air and determines when the air is cool
enough and dry enough to provide free cooling.
The rainhood is painted to match the basic unit and must
be field-assembled before installing.
•
BAS-READY ECONOMIZER -
Includes a slide-in / plug-in
damper assembly with fully modulating spring-return
motor actuator with zero to 95-degree rotation capable of
introducing up to 100% outdoor air with nominal 1% leak-
age type dampers.
Actuator requires 2-10 VDC input from an external source,
such as a field-installed or factory-installed BAS controller.
BAS-ready actuators have an adjustable auxiliary end-
switch for optional power exhaust control.
For units with optional VAV or Simplicity® Intelli-Comfort™
control, a factory-installed, dry bulb sensor determines if
outdoor air temperature is low enough to provide free-cool-
ing operation. (Field-installed humidity sensors for either
outdoor air or outdoor & return air streams are available for
single enthalpy and differential enthalpy configurations,
respectively).
The rainhood is painted to match the basic unit and must
be field-assembled before installing.
•
POWER EXHAUST
- Our economizer options are
available with power exhaust. Whenever the outdoor air
intake dampers are opened for free cooling, the exhaust
fan will be energized to prevent the conditioned space
from being over-pressurized during economizer operation.
BAS-ready economizer actuators have an adjustable
auxiliary end-switch to provide a range of damper positions
available to energize power exhaust. For units with optional
VAV, power exhaust is energized by means of a binary
output signal from the unit's VAV control board.
The exhaust fan, motor and controls are installed and
wired at the factory. The rain hood must be assembled
and installed in the field.
•
MOTORIZED OUTDOOR AIR INTAKE DAMPER
-
Includes a slide-in / plug-in damper assembly with a 2-
position, spring return motor actuator which opens to a pre-
set position whenever the supply air blower is operating
and will drive fully closed when the blower unit shuts down.
The rain hood is painted to match the basic unit and must
be field assembled before installing.
•
BAROMETRIC RELIEF DAMPER -
This damper option
can be used to relieve internal building air pressure on
units with an economizer without power exhaust. This
accessory includes a rain hood, a bird screen and a fully
assembled damper. With bottom duct connections, the
damper should be mounted over the opening in the return
air panel. With horizontal ductwork, the accessory should
be mounted on the return air duct.
•
PHENOLIC COATED EVAPORATOR, REHEAT, AND
CONDENSER COILS
- Special coating process that utilizes
Technicoat 10-1" processes. Coating is applied by total
immersion of the complete coil for maximum protection.
•
ELECTRIC HEATERS
wired for single point power
supply. These nickel chromium heater elements are
provided with limit and automatic reset capability to
prevent operation at excessive temperatures.
•
VARIABLE AIR VOLUME (VAV)
- A factory-installed
variable frequency drive (VFD), mounted in the Blower
Access compartment, is used to control the speed of the
indoor blower motor in order to maintain a constant static
pressure in the supply duct. A pressure transducer and
VAV control board are mounted inside the control box.
The drive comes completely wired and pre-programmed
from the factory.
An optional, factory-installed manual bypass switch avail-
able with factory-installed VFD can be found in the Blower
Motor Access compartment. The switch can be used to
either route power to the VFD for modulating control of the
blower motor, to bypass the drive and operate the motor
at full speed, or to power the drive (and not the motor) for
diagnostic purposes.
Due to space limitations, VAV is not available with any of
the factory-installed BAS options described below, but is
available with ‘BAS-ready’ models. Terminal blocks are
provided in the control box for field wiring of the customer-
installed BAS.
A ‘VFD-ready’ option provides the provisions for a cus-
tomer-installed drive. The unit comes with a mounting
bracket installed in the Blower Access compartment which
may accommodate other vendor’s drives depending on
their size. In order to utilize the unit’s mounting bracket, the
maximum recommended drive dimensions are as follows:
For 5-hp motor applications ........................13” H x 6” W x 7” D
For 7.5 thru 15-hp motor applications .........13” H x 8” W x 8” D
If the drive will not fit in the allotted space, then it will have to
be mounted elsewhere; either within the building on a per-
pendicular wall which is not subjected to excessive temper-
ature, vibration, humidity, dust, corrosive gas, explosive gas,
etc., or within an appropriate enclosure rated for outside
installation to safeguard against moisture, dust and exces-
sive heat.
A terminal block located in the control box is provided for
field connection of the VFD controls.
•
HOT GAS BYPASS
- To allow for low cooling load opera-
tion, a direct-acting pressure-modulating bypass control
valve installed on the system #1 discharge line is used to
divert high temperature, high pressure refrigerant around
the TXV in order to maintain a desired minimum evapora-
tor pressure. HGBP is standard on all units with VAV and
optional with CV units.
