78
SS-PRC003-EN
Mechanical
Specifications
Air Handlers
General
Air handler units shall be completely
factory assembled including coil,
condensate drain pan, fan motor(s),
filters, and controls in an insulated
casing that can be applied in either
vertical or horizontal configuration. Units
shall be rated and tested in accordance
with ARI standard 210/240, 340/360.
Casing
Unit casing shall be constructed of zinc
coated, heavy gauge, galvanized steel.
Exterior surfaces shall be cleaned,
phosphatized, and finished with a
weather-resistant baked enamel finish.
Casing shall be completely insulated
with cleanable, foil faced, fire- retardant,
permanent, odorless glass fiber material.
All insulation edges shall be either
captured or sealed. Knockouts shall be
provided for unit electrical power and
refrigerant piping connections. Captive
screws shall be standard on all access
panels.
Refrigeration System
The TWE050A, TWE075A, TWE100A units
shall have a single refrigeration circuit
and the TWE050B, TWE075B, TWE100B,
TWE155B, TWE200B units shall have
dual refrigeration circuits. Each
refrigeration circuit is controlled by a
factory installed thermal expansion
valve.
Evaporator Coil
Configured aluminum fin surface shall
be mechanically bonded to
3
/
8
” (10 mm)
internally enhanced copper tubing and
factory pressure and leak tested at 450
psig (3103 kPa). Coil is arranged for draw-
thru airflow and shall provide a double
sloped condensate drain pan constructed
of PVC plastic. The drain pan shall be
removable for cleaning. The condensate
drain pan can be installed in any of four
positions allowing for vertical or
horizontal application and providing
external connections on either side of the
unit.
Evaporator Fan
Double inlet, double width, forward
curved, centrifugal-type fan(s) with
adjustable belt drive shall be standard.
Thermal overload protection shall be
standard on motor. Fan and motor
bearings shall be permanently
lubricated. Oversized motors shall be
available as an option for high static
application.
Controls
Magnetic evaporator fan contactor, low
voltage terminal strip, check valve(s), and
single point power entry shall be
included. All necessary controls shall be
factory-installed and wired. Evaporator
defrost control shall be included to
prevent compressor slugging by
temporarily interrupting compressor
operation when low evaporator coil
temperatures are encountered.
Filters
One inch, throwaway filters shall be
standard on TWE050A, TWE075A,
TWE100A and TWE100B model air
handlers. Filters shall be accessible from
the side coil access panel. Filter rack can
be field converted to two-inch capability.
Two-inch throwaway filters shall be
standard on TWE155B, TWE200B and
TWE200E models.
Accessories
Electric Heaters
— Approved electric
heat modules shall be available for
installation directly on fan discharge.
Electric heaters shall be available in a
wide range of capacities with one or
two-stage control, single-point electric
power connection and terminal strip
connections. Electric heater elements
shall be constructed on heavy-duty
nickel chromium elements internally
wye connected on 480/600 volt, three
phase and delta connected on 208/240
volt, three phase. Each 208/240 volt,
three phase heater shall have pilot duty
with secondary backup fuse links for
automatic reset of high limit controls.
Each 480/600 volt heater shall have
automatic line break high limit controls.
Discharge Plenums and Grilles
—
Accessory discharge plenums shall be
available for vertical, free discharge
applications. Plenums shall be
constructed of heavy-gauge, zinc coated,
galvanized steel finished with baked
enamel to match the air handler unit.
Grilles shall be satin finished aluminum
and have four-way adjustable louvers.
Return Air Grilles
— Accessory return air
grille shall be provided for vertical front,
free return applications. Grilles shall be
installed in place of the front lower side
panel. Grille shall be satin finished
aluminum with non-adjustable louvers.
Mounting Subbase
— This accessory
shall be available for vertical floor mount
configurations. Subbase shall be
constructed of heavy gauge, zinc coated,
galvanized steel with baked enamel
finish to match air handler unit. Subbase
is required in the vertical air flow
application for condensate drain
trapping and when isolators are
required.
Vibration Isolators
— This accessory
shall reduce transmission of noise and
vibration to building structures,
equipment, and adjacent spaces.
Packages shall be available in either
neoprene-in shear or spring-flex types in
floor or suspended mountings.
Oversized Motors
— Field installed
oversized motors shall be available for
high static pressure applications.
Control Options
Standard Indoor Thermostats
— Two
stage heating and cooling operation or
one stage heating and cooling
thermostats shall be available in either
manual or automatic changeover.
Programmable Electronic Night Setback
Thermostat
— The option shall provide
heating setback and cooling setup with
7-day programming capability.
