P/N 3101069-EN • REV 005 • ISS 19OCT20    5 / 6 
Figure 7: Air pressure differential 
 
  Sampling tube 
  HVAC duct 
(5)  Air pressure differential 
meter 
  Sampling tube opening 
Testing the duct smoke detector 
After completing installation of the duct smoke detector, test the 
detector to ensure it is operating correctly prior to leaving the site. For 
details, refer to Application Bulletin P/N 3101107. 
Maintenance  
Replacement parts 
The following table lists the replacement parts for the duct smoke 
detector. 
Table 5: Replacement parts 
  Description 
-SDPCB   PCB replacement kit for duct smoke detector 
Cleaning the duct smoke detector 
Clean the duct smoke detector when it becomes 80% to 99% dirty or 
sooner if conditions warrant. 
Caution: Before cleaning the duct smoke detector, notify the proper 
authorities that the fire alarm system is undergoing maintenance and 
take steps to prevent the control panel from responding to a false 
alarm. 
To clean the duct smoke detector: 
1.  Disable the detector or zone to prevent false alarms. 
2.  Remove the detector’s cover, and then power down the detector 
by disconnecting the SLC wiring. See Figure 6. 
3.  Using a vacuum cleaner, clean compressed air, or a soft bristle 
brush, remove loose dirt and debris from inside the detector 
housing and cover. 
4.  Remove dirt and other contaminants from the gasket on the 
detector’s cover using isopropyl alcohol and a lint-free cloth. 
5.  Squeeze the retainer clips on both sides of the optic housing then 
lift the housing away from the printed circuit board. See Figure 8. 
6.  Gently remove dirt and debris from around the optic plate and 
inside the optic housing. 
7.  Replace the optic housing and the detector cover, and then 
connect the SLC wiring. 
8.  Test the detector and verify its sensitivity. For details, refer to 
Application Bulletin P/N 3101107. 
Figure 8: Duct detector cleaning 
 
  HVAC duct 
  Detector housing 
  Optic housing 
  Airflow 
Specifications 
 
Communication line voltage
  20 Vp-p max. 
 
Normal 
Alarm  
Inrush 
 
45 µA 
45 µA 
1 mA 
Common alarm relay/auxiliary 
equipment 
 
Quantity 
Type 
Rating 
Unsupervised and power-limited 
 
1 
Form C 
2.0 A at 30 VDC (resistive) 
  100 to 4,000 ft./min  
Air pressure differential
  0.005 to 1.00 in. of water 
  0.79 to 2.46%/ft. obscuration 
  Photoelectric (light scattering 
principle) 
response time  5 seconds 
  8.70 × 5.45 × 1.90 in. 
 
Temperature 
Relative humidity 
 
32 to 122°F (0 to 50°C) 
0 to 93%, noncondensing 
 
SD-TRM 
SD-TRK 
SD-MAG 
SD-VTK 
R-LED 
 
Remote test-reset station, magnetic 
Remote test-reset station, keyed 
Test magnet kit 
Air velocity test kit 
Remote LED alarm indicator