74
RT-PRC005-EN
Mechanical
Specifications
24-volt electromechanical control circuit
shall include control transformer and
contactor pressure lugs for power
wiring. Units shall have single point
power entry as standard.
Accessories/Options
Electric Heaters
— Factory or field-
installed electric heat modules shall be
available for installation within basic
unit. Electric heater elements shall be
constructed of heavy-duty nickel
chromium elements internally delta
connected for 240 volt, wye connected
for 480 and 600 volt. Staging shall be
achieved through the unitary control
processor (UCP). Each heater package
shall have automatically reset high limit
control operating through heating
element contactors. All heaters shall be
individually fused from the factory,
where required, and shall meet all NEC
and CEC requirements when properly
installed. Power assemblies shall provide
single-point connection. Electric heat
modules shall be UL listed or CSA
certified.
Roof Curb
—
The roof curb shall be
designed to mate with the unit’s
downflow supply and return and provide
support and a water tight installation
when installed properly. The roof curb
design shall allow field-fabricated
rectangular supply/return ductwork to be
connected directly to the curb. Curb
design shall comply with NRCA
requirements. Curb shall be shipped
knocked down for field assembly and
shall include wood nailer strips.
Economizer
—
This accessory shall be
either field or factory-installed and shall
be available with or without barometric
relief. The assembly includes fully
modulating 0-100 percent motor and
dampers, minimum position setting,
preset linkage, wiring harness with plug,
spring return actuator and fixed dry bulb
control. The barometric relief shall
provide a pressure operated damper that
shall be gravity closing and shall prohibit
entrance of outside air during the
equipment “off” cycle. Optional solid
state or differential enthalpy control shall
be available for either factory or field
installation. The factory-installed
economizer arrives in the shipping
position and shall be moved to the
operating position by the installing
contractor.
Powered Exhaust
— The field installed
powered exhaust, available for 6-10 ton
units, shall provide exhaust of return air,
when using an economizer, to maintain
better bulding pressurization.
Remote Potentiometer
—
The minimum
position setting of the economizer shall
be adjusted with this accessory.
Manual Outside Air Damper
— Factory
or field-installed rain hood and screen
shall provide up to 50 percent outside air.
Motorized Outside Air Dampers
—
Factory or field-installed manually set
outdoor air dampers shall provide up to
50 percent outside air. Once set, outdoor
air dampers shall open to set position
when indoor fan starts. The damper shall
close to the full closed position when
indoor fan shuts down.
Discharge Air Sensing
— This factory or
field-installed option provides true
discharge air sensing in heating models.
This sensor is a status indicator readable
through Tracer® or Tracker®. This option
is available for microprocessor
controlled units.
Oversized Motors
— Factory or field-
installed direct drive oversized motors
shall be available for high static
applications.
Through the Base Electrical Access
—
An electrical service entrance shall be
factory provided allowing electrical
access for both control and main power
connections inside the curb and through
the base of the unit. Option will allow for
field installation of liquid-tight conduit
and an external field-installed disconnect
switch.
Through the Base Electrical with
Disconnect Switch
— Factory-installed 3-
pole, molded case, disconnect switch
with provisions for through the base
electrical connections are available. The
disconnect switch will be installed in the
unit in a water tight enclosure with
access through a swinging door. Factory
wiring will be provided from the switch
to the unit high voltage terminal block.
The switch will be UL/CSA agency
recognized. Note: The disconnect switch
will be sized per NEC and UL guidelines
but will not be used in place of unit
overcurrent protection.
Through the Base Electrical with Circuit
Breaker
— This option is a factory-
installed, thermal magnetic, molded
case, HACR Circuit Breaker with
provisions for through the base electrical
connections. The circuit breaker will be
installed in a water tight enclosure in the
unit with access through a swinging
door. Factory wiring will be provided
from the switch to the unit high voltage
terminal block. The circuit breaker will
provide overcurrent protection, be sized
per NEC and UL guidelines, and be
agency recognized by UL/CSA.
Powered or Unpowered Convenience
Outlet
— This factory-installed option is a
GFCI, 120v/15amp, 2 plug, convenience
outlet, either powered or unpowered.
When the convenience outlet is
powered, a service receptacle disconnect
will be available. The convenience outlet
is powered from the line side of the
disconnect or circuit breaker, and
therefore will not be affected by the
position of the disconnect or circuit
breaker. This option can only be ordered
when the Through the Base Electrical
with either the Disconnect Switch or
Circuit Breaker option is ordered.
Clogged Filter/Fan Failure Switch
— A
dedicated differential pressure switch is
available, factory-installed, to achieve
active fan failure indication and/or
clogged filter indication. These
indications will be registered with either
a zone sensor with status indication
lights or an Integrated Comfort™
System. This option is available for
microprocessor controlled units.
Reference or Comparative Enthalpy
—
Factory-installed Reference or
Comparative Enthalpy option shall be
available when a factory-installed
Economizer is ordered. This option is
available for microprocessor controlled
units.
High Pressure Cutout
— This factory-
installed option is offered for units that
do not have High Pressure cutout as
standard. All 3-phase units with scroll
compressors include High Pressure
Cutout as standard.
Hinged Access Doors
— Sheet metal
hinges are available factory-installed on
the Filter/Evaporator, Supply Fan/Heat,
and the Compressor/Control Access
Doors.
