DH100ACDCLP System Sensor Duct Detector Wiring

Even though System Sensor has upgraded their 4 wire convention duct smoke detectors you will still come across many of the older DH100ACDCLP models.  In my experience, this is the most common convention 4 wire photoelectric duct smoke detector provided by mechanical contractors.

I have drafted up a very easy to follow low voltage wiring diagram for the connection of the System Sensor Duct Detector model DH100ACDCLP to any addressable fire alarm module.

If this method is followed, you can be confident that the duct detector will report alarm signals even if the circuit is open due to troubles.  Always make sure to land the IDC leads of the addressable monitor module to terminals #4 and #5 (N.O.) and jumper over to the supervisory contacts #5 to #14 and place your fire alarm resistor on terminals #3 and #4.  There is an internal relay between terminals #3 and #14 (N.C.) that will complete the circuit in a normal condition.

If a trouble condition on the System Sensor duct detector arises then the internal relay between #3 and #14 will open and remove the loop resistance.  This is why is important to have the alarm contacts directly on the alarm terminals #4 and #5.

I have seen other companies wiring these backwards which can potentially open you up for some serious liability.  Lets say worst case scenario, If the System Sensor duct detector cover is not securely fastened and the internal relay opens up, you will not get an alarm condition if the sensor registers smoke.


Check out this problem I faced on another System Sensor duct detector.

DH100 DD

Make sure to use photoelectric duct smoke detectors over ionization.  See why.