Bryant 581A/B - Manual (Page 3)

3
FEATURES/BENEFITS (cont)
The units can be easily converted from a vertical to a horizontal
duct configuration by relocating the panels supplied with the
unit (size 036-150 only).
To Convert 036-151 Units from vertical to horizontal discharge,
simply relocate 2 panels. The same basic unit can be used for a
variety of applications and can be quickly modified at the job-
site.
To Convert 155-300 Units from vertical to horizontal discharge,
use the optional horizontal supply/return adapter roof curb
(581A155,180 and 579F/580F180-300) or accessory conversion
kit (581A210-300). Please note that 581A210-300 units are
available from the factory configured for horizontal supply/return.
Convenient Duct Openings in the unit basepans permit side-
by-side or concentric duct connections (see Application data
section) without requiring internal unit modification.
NOTE: On units using horizontal supply and return, the acces-
sory barometric relief or power exhaust MUST be installed on
the return ductwork.
Thru-The-Bottom Service Connection Capability comes
standard with the rooftop unit to allow power and control wiring
and gas connections to be routed through the unit’s basepan,
thereby minimizing roof penetrations (to prevent water leaks).
(Thru-the-bottom gas connection requires thru-the-bottom
accessory kit.) Power, gas and control connections are made
on the same side of the unit to simplify installation.
The Non-Corrosive Sloped Condensate Drain Pan
(Size 036-150) permits either an external horizontal side con-
densate drain (outside the roof curb) or an internal vertical
bottom drain (inside the roof curb). Both options require an
external, field-supplied P-trap.
Standard 2-in. Throwaway Filters are easily accessed
through a removable panel located above the air intake hood.
No tools are required to change unit filters.
Belt-Driven Evaporator-Fan Motors (optional on 580F units
under 6 tons) allow maximum on-site flexibility without changing
motors or drives.
Low Voltage Wiring Connections are easily made thanks to
the large terminal board which is located for quick, convenient
access.
In addition, color-coded wires permit easy tracing and
diagnostics.
PROVEN COMPRESSOR RELIABILITY — Design techniques
feature computer-programmed balance between compressor,
condenser, and evaporator. Bryant-specified hermetic compres-
sors are equipped with compressor overcurrent and overtem-
perature protection to ensure dependability.
All units have Bryant’s exclusive Acutrol™ (036-150) or TXV
(thermostatic expansion valve) metering device (155-300)
which precisely controls refrigerant flow, preventing slugging
and flood-back, while maintaining optimum unit performance.
Refrigerant filter driers are standard.
INTEGRATED ECONOMIZERS AND OUTDOOR-AIR DAMP-
ERS — Available as options or accessories, economizers and
manual outdoor-air dampers introduce outdoor air which mixes
with the conditioned air, improving indoor-air quality and often
reducing energy consumption.
During a first stage call for cooling, if the outdoor-air tempera-
ture is below the economizer control changeover set point, the
mixed-air sensor modulates the economizer outdoor-air damper
open to take advantage of free cooling provided by the outside
air. When second-stage cooling is called for, the compressor is
energized in addition to the economizer. If the outdoor-air tem-
perature is above the changeover set point, the first stage of
compression is activated and the economizer damper stays at
minimum position.
Accessory upgrade kits allow for control by differential dry-bulb
temperature (outdoor vs return), outdoor air enthalpy
changeover, or more precise differential enthalpy control.
Units can be equipped with different economizer options to
meet specific controls applications. The factory-installed or
field-installed EconoMi$er IV and EconoMi$er2 are available.
The EconoMi$er IV is used with the standard rooftop unit con-
trols and includes an industry standard, stand-alone, solid-state
controller. The control can be used with a CO
2
sensor for DCV
(demand control ventilation) operation. For direct digital control
(DDC) applications, the EconoMi$er2 can be operated using a
third party control system. The EconoMi$er2 includes 4 to
20 mA actuator capability for demand control ventilation
applications.
All economizers incorporate a parallel blade, gear-driven
damper system for efficient air mixing and reliable control. In
addition, the standard damper actuator includes a spring return
to provide reliable closure on power loss. The economizers for
sizes 036-151 are equipped with up to 100% barometric relief
capability for high outdoor airflow operations. Economizers for
unit sizes 036-151 are available, factory-installed, for vertical
return only. Economizers for unit sizes 155-300 are compatible
for vertical or horizontal return. An optional field-installed baro-
metric relief package is available for size 155-300 units.
In addition, single-stage power exhaust is available as a field-
installed accessory for EconoMi$er IV to help maintain proper
building pressure.
For units without economizer, year-round ventilation is
enhanced by an optional manual outdoor-air damper. On 036-
150 units, a 25% or 50% manual damper is available as a field-
installed accessory. Unit sizes 155-300 are equipped with a
manual 25% damper.
SERVICE OPTIONS (581B and 581A Units Only) — Servicing
a rooftop unit has never been easier with the factory-installed
service options for these rooftop units. These options include
the following:
• Hinged access panels are provided for the filter/indoor-fan
motor, compressors, evaporator fan, and control box areas.
Quick access to major components is accomplished by simply
unlatching and swinging open the various panels. Each
hinged panel is permanently mounted to the unit, thereby
eliminating the concern of a dropped or wind-blown panel
puncturing delicate roof materials. The 4 extended access
panels are also equipped with ‘‘tie back’’ retaining devices to
hold the door in the open position while servicing the unit.
• An external, covered, 115-v Ground Fault Interrupt (GFI)
receptacle is provided as a convenient power source for drills,
lights, refrigerant recovery units, or other electrical service
tools. A factory-supplied step down transformer is connected
to the “load” side of the unit main power connection (size 036-
150). For sizes 155-300, connect the outlet to a field-supplied
and properly fused branch circuit power supply.
• Slide out “motor-drive-blower” reduces service time (only on
581A210-300).
• An integral non-fused disconnect switch within the rooftop unit
reduces installation time, labor and material costs. Safety is
assured by an interlock which prevents access to the control
box unless the switch is in the OFF position. In addition, the
externally mounted handle incorporates power lockout capa-
bility to further protect service personnel.