Sensor; Smoke Detector Locations - Carrier WeatherMaster Puron 48HC D17 Service And Maintenance Instructions

Duct smoke sensor
Controller housing
and electronics
Conduit couplings
(supplied by installer)
Fastener
(2X)
Alarm
Fig. 30 — Controller Assembly

Sensor

The sensor includes a plastic housing, a printed circuit board, a
clear plastic cover, a sampling tube inlet and an exhaust tube.
See Fig. 31. 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 plas-
tic cover permits visual inspections without having to disas-
semble the sensor. The cover attaches to the sensor housing us-
ing 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: Power, Trouble, Alarm and Dirty. A manual test/re-
set button is located 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 pressure between the
two tubes pulls the sampled air through the sensing chamber.
When a sufficient amount of smoke is detected 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 handling systems, notify the fire
alarm control panel, etc.
controller
Conduit nuts
(supplied by installer)
Conduit support plate
Terminal block cover
Cover gasket
(ordering option)
Controller cover
Trouble
Power
Test/reset
switch
The sensor uses a photoelectric (light scattering principle) pro-
cess called differential sensing preventing gradual environmen-
tal changes from triggering false alarms. A rapid change in en-
vironmental conditions, such as smoke from a fire, causes the
sensor to signal an alarm state, but dust and debris accumulated
over time does not.
Exhaust tube
See
Detail A
Intake
gasket
TSD-CO2
(ordering option)
Plug
Sampling tube
(ordered separately)
Coupling
Detail A
Magnetic
test/reset
switch
Fig. 31 — Smoke Detector Sensor
For installations using two sensors, the duct smoke detector
does not differentiate which sensor signals an alarm or trouble
condition.

Smoke Detector Locations

SUPPLY AIR
The supply-air smoke detector sensor is located to the left of
the unit's indoor supply fan. See Fig. 32. Access is through the
fan access panel. There is no sampling tube used at this loca-
tion. The sampling tube inlet extends through the side plate of
the fan housing into a high pressure area. The control module
is mounted in the left side of the control box, accessed by
opening the control box access door.
26
Duct smoke sensor
Exhaust gasket
Sensor housing
and electronics
Cover gasket
(ordering option)
Alarm Power
Trouble Dirty
Sensor cover