Carrier 50TCQD Installation Instructions Manual page 35

Smoke Detectors
Smoke detectors are available as factory- - installed options
on 50TCQD 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
shutdown operation; additional wiring or modifications to
unit terminal board may be necessary to complete the unit
and smoke detector configuration to meet project
requirements.
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 as a life saving device.
Controller
The controller (see Fig. 57) 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 screw for easy access to the
wiring terminals. The controller has three LEDs (for
Power, Trouble and Alarm) and a manual test/reset button
(on the cover face).
Sensor
The sensor (see Fig. 58) 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 is shipped in the blower section and is
wire tied to the blower housing. 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 terminal for connecting to the controller.
Each sensor has four LEDs (for Power, Trouble, Alarm
and Dirty) and a manual test/reset button (on the left- - side
of the housing).
Air is introduced to the duct smoke detector sensor's sensing
chamber through a sampling tube that extends into the
HVAC duct and is directed back into the ventilation system
through a (shorter) exhaust tube. The difference in air pres-
sure between the two tubes pulls the sampled air through the
sensing chamber. When a sufficient amount of smoke is de-
tected in the sensing chamber, the sensor signals an alarm
state and the controller automatically takes the appropriate
action to shut down fans and blowers, change over air hand-
ling systems, notify the fire alarm control panel, etc.
immediate smoke detector
Duct smoke sensor
controller
Controller housing
and electronics
Conduit couplings
(supplied by installer)
Fastener
(2X)
Alarm
Fig. 57 - - Controller Assembly
Duct smoke sensor
Exhaust tube
Intake
gasket
TSD-CO2
(ordering option)
Magnetic
test/reset
switch
Alarm
Trouble
Fig. 58 - - Smoke Detector Sensor
35
Conduit nuts
(supplied by installer)
Conduit support plate
Terminal block cover
Cover gasket
(ordering option)
Controller cover
Trouble
Power
Test/reset
switch
C08208
Sensor housing
and electronics
Cover gasket
(ordering option)
Sensor cover
Power
Dirty
C09070