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. 18. 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
Smoke Detector Sensor
C08245
Fig. 18 - 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. 19. 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
Return Air Detector module (shipping position shown)*
Controller module
Return Air Detector Sampling Tube
*RA detector must be moved from shipping position to operating position by installer
C07307
Fig. 19 - 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. 20. 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
50TC
Return Air
Sampling Tube
C08129
Fig. 20 - Return Air Sampling Tube Location
Completing Installation of Return Air Smoke Sensor:
Screws
Flexible
Exhaust Tubes
Sample Tube
C08126
Fig. 21 - Return Air Detector Shipping Position
1.Unscrew the two screws holding the Return Air Sensor detector plate. See Fig 21. Save the screws.
2.Remove the Return Air Sensor and its detector plate.
3.Rotate the detector plate so the sensor is facing out- wards and the sampling tube connection is on the bot- tom. See Fig 22.
4.Screw the sensor and detector plate into its operating position using screws from Step 1. Make sure the sampling tube connection is on the bottom and the ex- haust tube is on the top. See Fig 22.
5.Connect the flexible tube on the sampling inlet to the sampling tube on the basepan.
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