18 • 35-3001-13-02 Carbon Dioxide/Oxygen Sample-Draw Detector
5. If the calibration/response difficulties continue, replace the sensor as described later in this section.
6. If the calibration/response difficulties continue, contact RKI Instruments, Inc. for further instruction.
Replacing Components of the Sample-Draw Detector
This section includes procedures to replace the IR CO
2
gas sensor, oxygen sensor, hydrophobic filter, and
particle filter.
Replacing the IR CO
2
Gas Sensor
1. Turn off the controller.
2. Turn off power to the controller.
3. Open the housing door of the sample-draw detector.
4. Unscrew and remove the four screws that secure the IR CO
2
sensor PCB, then lift the IR CO
2
sensor PCB
and sensor off of the flow block.
There is a gasket at the bottom of the flow block. Be sure the gasket stays in place.
5. Unplug the sensor from the IR CO
2
sensor PCB.
6. Verify that you are using the correct replacement sensor, then plug the sensor into the IR CO
2
sensor PCB.
7. Place the sensor and sensor PCB in the carbon dioxide sensor cavity.
8. Secure the sensor PCB on the flow block with the four screws you removed in step 4.
9. Close and latch the housing door.
10. Turn on power to the controller.
11. Turn on the controller.
CAUTION:
Allow the replacement sensor to warm up for 5 minutes before you continue.
12. Calibrate the replacement sensor as described in “Calibration, IR CO
Replacing the Oxygen Sensor
1. Turn off the controller.
2. Turn off power to the controller.
3. Open the housing door of the sample-draw detector.
4. Loosen the two screws on the oxygen terminal strip and remove the lugs and wires from the terminal strip.
5. Unscrew and remove the two screws that secure the sensor retaining plate, then lift the plate and sensor out
of the flow block.
There is a gasket at the bottom of the flow block. Be sure the gasket stays in place.
6. Place the replacement sensor in the oxygen flow block, then position the retaining plate on the two standoffs.
7. Secure the retaining plate to the standoffs with the two screws you removed in step 4.
8. Guide the wires and lugs of the replacement sensor to the oxygen terminal strip and insert each lug into the
appropriate terminal. See Figure 4 on page 14 for wiring connections. Tighten the screws on the terminal
strip.
9. Close and latch the housing door.
10. Turn on power to the controller.
11. Turn on the controller.
