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RTU−OPEN CONTROL SYSTEM
The RTU Open controller is an integrated component of
the Carrier rooftop unit. Its internal application
programming provides optimum performance and energy
efficiency. RTU Open enables the unit to run in 100%
stand−alone control mode, Carrier’s I−Vu Open network,
or a Third Party Building Automation System (BAS).
On−board DIP switches allow you to select your protocol
(and baud rate) of choice among the four most popular
protocols in use today: BACnet, Modbus, Johnson N2 and
LonWorks.
The RTU Open control is factory−mounted in the 50TC
unit’s main control box, to the left of the Light
Commercial Terminal Board (LCTB). See Fig. 44.
Factory wiring is completed through harnesses connected
to the LCTB. Field connections for RTU Open sensors
will be made at the Phoenix 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$er2 package.
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 controller may also require connection to a
building network system or building zoning system. All
field control wiring that connects to the RTU−OPEN must
be routed through the raceway built into the corner post of
the unit or secured to the unit control 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 Phoenix
connectors and then reconnect the connectors to the board.
See Fig. 44.
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 or death, and/or equipment damage.
Disconnect and lockout/tagout electrical power before
wiring the RTU−OPEN controller.
!
WARNING
Additional RTU−OPEN Installation and
Troubleshooting
Additional installation, wiring and troubleshooting
information for the RTU−OPEN Controller can be found
in the following manuals: “Controls, Start−up, Operation
and Troubleshooting Instructions,” and “RTU Open
Installation and Start−up Guide.”
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