333491-YTG-B-0807
6
Unitary Products Group
rails shall be removable, when required, to lower unit height.
Filters shall be furnished and be accessible through a
removable access door, sealed airtight. Units vertical discharge
and return duct configuration shall be designed to fit between
standard 24” O.C. beams without modification to building
structure, duct work and base unit. Condensate pan shall be
internally sloped and conform to ASHRAE 62-89 self-draining
standards, with 3/4” NPTI copper, ridged mount connection.
Indoor (Evaporator) Fan Assembly
Fan shall be direct drive design. Fan wheel shall be double-inlet
type with forward-curved blades, dynamically balanced to
operate smoothly throughout the entire range of operation.
Airflow design shall be constant air volume. Bearings shall be
sealed and permanently lubricated for longer life and no
maintenance. Fan assembly shall be “Slip Track” (slide-out)
design for easy removal and cleaning.
Outdoor (Condenser) Fan Assembly
The outdoor fan shall be of the direct-driven propeller type,
discharge air vertically, have aluminum blades riveted to
corrosion resistant steel spider bracket and shall be statically
balanced for smooth operation. The outdoor fan motor shall be
totally enclosed with permanently lubricated bearings and
internally protected against overload conditions.
Refrigerant Components
Compressors:
a. Shall be fully hermetic type, direct drive, internally
protected with internal high-pressure relief and over
temperature protection. The hermetic motor shall be
suction gas cooled and have a voltage range of +/- 10%
of the unit nameplate voltage.
b. Shall have internal isolation and sound muffling to
minimize vibration and noise, and be externally isolated
on a dedicated, independent mounting.
Coils:
a. Evaporator and condenser coils shall have aluminum
plate fins mechanically bonded to seamless internally
enhanced copper tubes with all joints brazed.
b. Evaporator coil shall be of the direct expansion, blow
through design, while condenser coil shall be draw
through design.
Refrigerant Circuit and Refrigerant Safety Components shall
include:
a. Shall include independent fixed orifice expansion
devices.
b. Shall include filter/strainer to eliminate any foreign
matter.
Gas Heating Section (If Equipped)
Heat exchanger and exhaust system shall be constructed of
aluminized steel and shall be designed with induced draft
combustion with post purge logic and redundant main gas
valve. The heat exchanger shall be of the tubular type,
constructed of T1-40 aluminized steel for corrosion resistance
and allowing minimum mixed air entering temperature of 40 ºF.
Burners shall be of the in-shot type, constructed of aluminum-
coated steel. All gas piping shall enter the unit cabinet at a
single location through either the side or bottom, without any
field modifications. An integrated control board shall provide
timed control of evaporator fan functioning and burner ignition.
Heating section shall be provided with the following minimum
protection:
a. Primary and auxiliary high-temperature limit switches.
b. Induced draft pressure sensor.
c. Flame roll out switch (manual reset).
d. Flame proving controls.
