Carrier 48TC*D08 appendix Smoke Detector Locations, Smoke Detector Sensor

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.

Duct smoke sensor

Smoke Detector Sensor

C08245

48TC

Exhaust tube

Exhaust gasket

See

Detail A

Intake gasket

TSD-CO2 (ordering option)

Plug

Sampling tube

(ordered separately)

Coupling

Detail A

Magnetic test/reset switch

Sensor housing and electronics

Cover gasket

(ordering option)

Sensor cover

Fig. 20 - Typical Supply Air Smoke Detector Sensor

Location

Return Air without Economizer — The sampling tube is located across the return air opening on the unit basepan. (See Fig. 21.) The holes in the sampling tube face downward, into the return air stream. The sampling tube is connected via tubing to the return air sensor that is mounted on a bracket high on the partition between return filter and controller location. (This sensor is shipped in a flat-mounting location. Installation requires that this sensor be relocated to its operating location and the tubing to the sampling tube be connected. See installation steps below.)

Return Air Detector module (shipping position shown)*

Alarm	Power
Trouble	Dirty

C08209

Fig. 19 - 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. 20.) Access is through the fan access panel. There is no sampling tube used at this location. The sampling tube inlet extends through the side plate of the fan housing (into a high pressure area). The controller is located on a bracket to the right of the return filter, accessed through the lift-off filter panel.

Controller module

Return Air Detector Sampling Tube

*RA detector must be moved from shipping position to operating position by installer

C07307

Fig. 21 - Typical Return Air Detector Location

Return Air with Economizer — The sampling tube is inserted through the side plates of the economizer housing, placing it across the return air opening on the unit basepan. (See Fig. 22.) The holes in the sampling tube face downward, into the return air stream. The sampling tube is connected via tubing to the return air sensor that is mounted on a bracket high on the partition between return filter and controller location. (This sensor is shipped in a flat-mounting location. Installation requires that this sensor be relocated to its operating location and the tubing to the sampling tube be connected. See installation steps below.)

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