16 • 65-2397SS CO
2
Transmitter
Replacing Components of the CO
2
Transmitter
This section includes a procedure to replace the hydrophobic membrane, a procedure to replace the
plug-in IR CO
2
sensor, a procedure to replace the entire CO
2
detector assembly, and one to replace the
amplifier. In most cases, it is not necessary to replace the entire detector assembly.
Replacing the Hydrophobic Membrane
1. Turn off the controller.
2. Turn off or unplug incoming power to the controller.
3. Unscrew the detector housing cap from the detector housing body.
4. Gently pry up the edge of the white hydrophobic membrane with a small flat blade screwdriver or
a similar tool.
5. Peel off the hydrophobic membrane. It may be necessary to clean off the detector housing cap face
to remove any residue left from the adhesive-backed membrane.
6. Install the new membrane in the recess on the face of the detector housing cap.
7. Make sure the cap gasket is in place and screw the detector housing cap back onto the detector
housing body.
8. Turn on the power to the controller.
9. Turn on the controller and place it into normal operation.
NOTE:
When first powered up, the transmitter will enter about a one minute period when the 4-20
mA output is stabilizing and may be above the controller alarm points or well below zero
momentarily. RKI controllers have a one minute warmup period when the controller does not
display any gas reading or give any alarm indication. The combustible gas transmitter’s 4-20
mA signal should be stable by the time the controller’s warmup period is over.
Replacing the Plug-In CO
2
Sensor
1. Turn off the controller.
2. Turn off or unplug power to the controller.
3. Unscrew the detector housing cap from the detector housing body. Make sure not to lose the cap
gasket.
4. Unplug and remove the plug-in IR CO
2
sensor.
5. Carefully plug the replacement sensor into the socket pattern that is located in the detector
housing.
6. Make sure the cap gasket is in place and screw the detector housing cap back onto the detector
housing body.
7. Turn on power to the controller.
8. Turn on the controller and place it into normal operation.
