20 • 35-3001A-10 Oxygen/Carbon Monoxide Sample-Draw Detector
4. If you cannot set the correct flow rate, check the sample line for obstructions or kinks.
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 oxygen sensor, CO sensor, oxygen amplifier, CO
amplifier, hydrophobic filter, and particle filter.
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 6 on page 16 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.
CAUTION:
Allow the replacement sensor to warm up for 5 minutes before you continue.
12. Calibrate the replacement sensor as described in “Calibration, Oxygen Sensor” on page 25.
Replacing the CO 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 two screws that secure the CO amplifier, then lift the CO amplifier 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 CO amplifier.
6. Verify that you are using the correct replacement sensor, then plug the sensor into the CO
amplifier.
7. Place the sensor and amplifier in the CO sensor cavity.
