65-2397SS CO
2
Transmitter • 7
Infrared CO
2
Detector
The CO
2
detector consists of the detector housing body, detector housing cap, cap gasket,
and the plug-in sensor.
Figure 2: CO
2
Detector Component Location
Detector Housing Body
The detector housing body protects the electronic components within the housing. Use the mounting
threads at the top of the housing to screw the CO
2
detector into the 3/4 NPT hub on the bottom of the
junction box. Four color coded leads, red, white, green, and black, extend from the other end of the
detector. The leads allow you to connect the detector to the amplifier.
The housing includes three sockets installed on a circuit board. These sockets accept the plug-in
sensor’s three pins to provide an electrical connection for the sensor. The circuit board with the sockets
conditions the sensor’s signal before the signal reaches the amplifier.
Housing Cap & Cap Gasket
The housing cap screws onto the detector housing. It retains the plug-in sensor and protects it from
damage. A foam gasket is installed inside the housing cap that seals against the sensor face. A
hydrophobic membrane on the outside of the cap face keeps water and particulates away from the
sensor face behind the cap. Unscrew the detector cap to access the plug-in sensor for maintenance or
replacement. A cap gasket seals the interface between the housing and cap.
Plug-In CO
2
Sensor
The plug-in sensor is secured in the detector assembly by the housing cap. The sensor produces a
millivolt output that corresponds to the detection range of the transmitter.
Hydrophobic
Membrane
Cap Gasket
Plug-In CO2 Sensor
Sensor Retainer
Detector Housing Cap
Detector Housing Body
