33
Table9 – LEDs
The LEDson the RTU--MPshow the status of certain functions
Ifthis LED is on... Statusis...
Power The RTU MP has power
Rx TheR TU MP is receiving data from the networksegment
Tx The RTU MP is transmitting data over the network segment
DO# Thedigital outp ut is active
TheRun and Error LE Ds indicatecontrol module and network status
If Run LED shows... And Error LED shows... Statusis...
2flashes p er second Off Normal
2flashes p er second 2flashes,
alternatingwith Run LED Five m inuteauto ---restartdelay after system error
2flashes p er second 3flashes,
then off Controlmodule has just been formatted
2flashes p er second 4flashes,
then pause
Twoor more devices on thi s network have the
same ARC156 network address
2flashes p er second On Exec halted after frequent system errors or
controlprogra ms halted
5flashes p er second On Exec start---up aborted, Boot is running
5flashes p er second Off Firmware transfer in progress, Boot is running
7flashes p er second 7 flashes per second, alternating with
Run LED Tensecond recovery period after brownout
14flashes per second 14flashesper second,
alternatingwith Run LED Brownou t
On On
Failure.Try the following solutions:
STurnthe RTU ---MPoff, then on.
SFor m a t t h e R TU --- M P.
SDownloadmemory to the RTU---MP.
SReplacethe RTU---MP.
NOTE: Refer to Form 48--50H--T--2T for complete
configuration of RTU--MP, operating sequences and
troubleshooting information. Refer to RTU--MP3rd Party
Integration Guide for details on configuration and
troubleshooting of connected networks. Have a copy of
these manuals available at unit start--up.

SMOKE DETECTORS

Smoke detectors are available as factory--installed options
on 50TCQ models. Smoke detectors may be specified for
Supply Air only or for Return Air without or with
economizer or in combination of Supply Air and Return
Air. Return Air smoke detectors are arranged for vertical
return configurations only. All components necessary for
operation are factory--provided and mounted. The unit is
factory--configured for immediate smoke detector
shutdown operation; additional wiring or modifications to
unit terminal boardmay be necessary to complete the unit
and smoke detector configuration to meet project
requirements.
Units equipped with factory--optional Return Air smoke
detectors require a relocation of the sensor module at unit
installation. See “Completing Installation of Return Air
Smoke Sensor:” on page 35 for details.

System

The smoke detector system consists of a four--wire
controller and one or two sensors. Its primary function is
to shut down the rooftop unit in order to prevent smoke
from circulating throughout the building. It is not to be
used asa life savingdevice.

Controller

The controller (see Fig. 58) includes a controller housing,
a printed circuit board, and a clear plastic cover. The
controller can be connected to one or two compatible duct
smoke sensors. The clear plastic cover is secured to the
housing with a single captive screwfor easy access to the
wiring terminals. The controller has three LEDs (for
Power, Trouble and Alarm) and a manual test/reset button
(on the coverface).
Sensor
The sensor (see Fig. 59) includes a plastic housing, a
printed circuit board, a clear plastic cover, a sampling
tube inlet and an exhaust tube. The sampling tube (when
used) and exhaust tube are attached during installation.
The sampling tube varies in length depending on the size
of the rooftop unit.The clear plastic cover permits visual
inspections without having to disassemble the sensor. The
cover attaches to the sensor housing using four captive
screws and forms an airtight chamber around the sensing
electronics. Each sensor includes a harness with an RJ45
50TCQA