Smoke Detector Locations - Carrier 48JC04-06 Service And Maintenance Instructions

appropriate action to shut down fans and blowers, change over
air handling systems, notify the fire alarm control panel, etc.
The sensor uses a process called differential sensing to prevent
gradual environmental changes from triggering false alarms. A
rapid change in environmental conditions, such as smoke from
a fire, causes the sensor to signal an alarm state but dust and
debris accumulated over time does not.
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.
For installations using two sensors, the duct smoke detector
does not differentiate which sensor signals an alarm or trouble
condition.
EXHAUST TUBE
A
SEE DETAIL
INTAKE
GASKET
TSD-CO2
(ORDERING OPTION)
PLUG
SAMPLING TUBE
(ORDERED SEPARATELY)
COUPLING
A
DETAIL
MAGNETIC
TEST/RESET
SWITCH
Fig. 31 — Smoke Detector Sensor

Smoke Detector Locations

SUPPLY AIR
The supply air smoke detector sensor is located to the right of
the unit's indoor (supply) fan. See Fig. 32. Access is through
the fan access panel. The sampling tube inlet extends through
the fan deck (into a high pressure area). The controller is locat-
ed on a bracket to the right of the return filter, accessed through
the lift-off filter panel.
DUCT SMOKE SENSOR
EXHAUST GASKET
SENSOR HOUSING
AND ELECTRONICS
COVER GASKET
(ORDERING OPTION)
SENSOR
COVER
ALARM POWER
TROUBLE
DIRTY
SUPPLY AIR
SMOKE DETECTOR
Fig. 32 — Typical Supply Air Smoke Detector Sensor
RETURN AIR SMOKE DETECTOR SENSOR WITHOUT
ECONOMIZER
The sampling tube is located across the return air opening on
the unit basepan. See Fig. 33. The holes in the sampling tube
face downward, into the return air stream. The sampling tube is
connected through tubing to the return air sensor that is mount-
ed on a bracket high on the partition between return filter and
controller location. The sensor is shipped in a flat-mounting lo-
cation. Installation requires that this sensor be relocated to its
operating location and the tubing to the sampling tube be con-
nected. See installation steps.
RETURN AIR
SMOKE DETECTOR
(AS SHIPPED)
Fig. 33 — Typical Return Air Smoke Detector
19
Location
Location