Duct Detector

Model 4098-9755 Basic Duct Sensor Housing
Model 4098-9756 Duct Sensor Housing with supervised output for multiple remote relays

Operation. Simplex® compact air duct smoke sensor housings provide TrueAlarm operation for the detection of smoke in air conditioning or ventilating ducts. Sampling tubes are installed into the duct allowing air to be directed to the smoke sensor mounted in the housing.

Compact air duct sensor housing with clear cover to monitor for the presence of smoke**

Includes factory installed TrueAlarm photoelectric smoke sensor and features:

  • Individual sensor information processed by the host control panel to determine sensor status
  • Digital transmission of analog sensor values via IDNet or MAPNET II, 2-wire communications
  • Programmable sensitivity, consistent accuracy, environmental compensation, status testing, and monitoring of sensor dirt accumulation

Model 4098-9755:

  • Basic duct sensor housing (no relay output) powered by IDNet/MAPNET II communications

Model 4098-9756:

  • Duct sensor housing with supervised output for multiple remote relays; requires separate 24 VDC; includes one relay
  • Relay output is under panel control
  • At the panel, relay output can be activated manually or in response to a separate alarm or other input

General features:

  • UL listed to Standard 268A
  • Clear cover allows visual inspection
  • Test ports provide functional smoke testing access with cover in place
  • Mounts to rectangular ducts or round ducts; minimum size is 8” (203 mm) square or 18” (457 mm) diameter
  • Magnetic test feature for alarm initiation at housing
  • Optional weatherproof enclosure is available separately (refer to data sheet S4098-0032)

Diagnostic LEDs (on interface board):

  • Red Alarm/Trouble LED for sensor status and communications polling display
  • Yellow LED for open or shorted trouble indication of supervised relay control (4098-9756 only)

Sampling tubes (ordered separately):

  • Available in multiple lengths to match duct size
  • Installed and serviced with housing in place

Remote module options (ordered separately):

  • Remote red status/alarm LED (2098-9808)
  • Remote test station with LED (2098-9806)
  • 4098-9843 remote relays (refer to page 2 for details)

* These products have been approved by the California State Fire Marshal (CSFM) pursuant to Section 13144.1 of the California Health and Safety Code. See CSFM Listing 3240-0026.241 for allowable values and/or conditions concerning material presented in this document. Accepted for use – City of New York Department of Buildings – MEA35-93E. Additional listings may be applicable; contact your local Simplex product supplier for the latest status. Listings and approvals

Digital Communication of Analog Sensing.
Analog information from the sensor is digitally communicated to the control panel where it is analyzed. Sensor input is stored and tracked as an average value with an alarm or abnormal condition being determined by comparing the sensor’s present value against its average.

Intelligent Data Evaluation.
Monitoring each photoelectric sensor’s average value provides a software filtering process that compensates for environmental factors (dust, dirt, etc.) and component aging, providing an accurate reference for evaluating new activity. The result is a significant reduction in the probability of false or nuisance alarms caused by shifts in sensitivity, either up or down.

Control Panel Selection.
Peak activity per sensor is stored to assist in evaluating specific locations. The alarm set point for each sensor is determined at the control panel, selectable as the individual application requires.

Sensor Status LED.
Each sensor housing’s red status LED (located on the electrical interface board) pulses to indicate communications with the panel. If the control panel determines that a sensor is in alarm, or that it is dirty or has some other type of trouble, the details are annunciated at the control panel and that sensor housing’s status LED will be turned on steadily. During a system alarm, the control panel will control the LEDs such that an LED indicating a trouble will return to pulsing to help identify any alarmed sensors. (Remote Status/Alarm LEDs track the operation of the sensor housing LED.)

TrueAlarm photoelectric sensors use a stable, pulsed infrared LED light source and a silicon photodiode receiver to provide consistent and accurate low power smoke sensing.

Typically duct sensor applications require less sensitive settings (such as 2.5% per foot obscuration) due to the ducts being a relative dirty environment. However, the standard seven levels of TrueAlarm sensor sensitivity are available for each individual sensor, ranging from 0.2% to 3.7% per foot of smoke obscuration. Sensitivity is selected and monitored at the fire alarm control panel.

  • Individual smoke sensitivity selection
  • Sensitivity monitoring that satisfies NFPA 72 sensitivity testing requirements
  • Peak value logging allows accurate analysis for sensitivity selection
  • Automatic, once per minute individual sensor calibration check verifies sensor integrity
  • Automatic environmental compensation
  • Smoke sensitivity is displayed in percent per foot
  • Ability to display and print detailed sensor information in plain English language
  • Relays of model 4098-9756 are under panel control for ON, OFF, or override