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SUPPLY (INDOOR) FAN MOTOR PROTECTION
Disconnect and lockout power when servicing fan motor.
The standard supply fan motor is equipped with internal over-
current and over-temperature protection. Protection devices re-
set automatically.
The high static option supply fan motor is equipped with a
pilot-circuit Thermix combination over-temperature/over-
current protection device. This device resets automatically. Do
not bypass this switch to correct trouble. Determine the cause
and correct it.
CONDENSER FAN MOTOR PROTECTION
The condenser fan motor is internally protected against over-
temperature.
Relief Device
A soft solder joint at the suction service access port provides
pressure relief under abnormal temperature and pressure condi-
tions (i.e., fire in building). Protect this joint during brazing op-
erations near this joint.
Control Circuit, 24-V
The control circuit is protected against overcurrent conditions
by a circuit breaker mounted on control transformer TRAN.
Reset is manual.
RTU OPEN CONTROL SYSTEM
The RTU Open controller is an integrated component of the
Bryant rooftop unit. Its internal application programming pro-
vides optimum performance and energy efficiency. RTU Open
enables the unit to run in 100% stand-alone control mode or us-
ing a Third Party Building Automation System (BAS). On-
board DIP switches allow the user to select your protocol (and
baud rate) of choice among the four most popular protocols in
use today: BACnet, Modbus
See Fig. 53.
1. Third-party trademarks and logos are the property of their respective
owners.
1
, Johnson N2 and LonWorks
The RTU Open control is factory-mounted in the unit's main
control box, to the left of the UCB (unit control board). Factory
wiring is completed through harnesses connected to the UCB.
Field connections for RTU Open sensors will be made at the
PCB connectors on the RTU Open board. The factory-installed
RTU Open control includes the supply-air temperature (SAT)
sensor. The outdoor air temperature (OAT) sensor is included
in the FIOP/accessory EconoMi$er
Sensory/Accessory Installation
There are a variety of sensors and accessories available for the
RTU Open. Some of these can be factory or field installed,
while others are only field installable. The RTU Open control-
ler may also require connection to a building network system
or building zoning system. All field control wiring that con-
nects to the RTU Open must be routed through the raceway
built into the corner post of the unit or secured to the unit con-
trol box with electrical conduit. The unit raceway provides the
UL required clearance between high and low-voltage wiring.
Pass the control wires through the hole provided in the corner
post, then feed the wires thorough the raceway to the RTU
Open. Connect the wires to the removable PCB connectors and
then reconnect the connectors to the board.
IMPORTANT: Refer to the specific sensor or accessory
instructions for its proper installation and for rooftop unit
installation refer to base unit installation instructions and the
unit's wiring diagrams.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury, death and/or equipment damage.
Disconnect and lockout/tag-out electrical power before
1
.
wiring the RTU Open controller.
29
®
2 package.
WARNING
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Troubleshooting
