10
65-2661RK-XX-04 M2A Transmitter Operator’s Manual
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 M2A.
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 controller.
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 detector.
Calibration Adapter/Splash Guard
A calibration adapter/splash guard is installed on the IR CO
2
detector. A fitting at the bottom of the calibration
adapter/splash guard allows a length of tubing to be connected for calibration and routed to a more easily
accessible location (near the M2A junction box is optimal for ease of calibration). The calibration adapter/splash
guard also protects the detector from splashing water or direct water spray.
Magnetic Wand
The magnetic wand is a short plastic rod with a magnet in one end. It is used to actuate the magnetic control
switches on the control PCB while the junction box cover is still installed so that non-intrusive calibration can be
performed.
