35-3001-05-03 Carbon Dioxide Sample-Draw Detector • 13
properly.
•
The sample-draw detector’s flow rate is too low because of an obstructed sample line, failed
pump, etc.
•
The sample-draw detector is malfunctioning.
Recommended action
1. Verify that the calibration cylinder contains an adequate supply of a fresh test sample.
2. If a demand flow regulator calibration kit is used, use a different demand flow regulator to
determine if the original one is functioning properly.
3. If necessary, set the correct flow rate with the sensor flow control valve.
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 Carbon Dioxide Sample-Draw Detector
This section includes procedures to replace the sensor, hydrophobic filter, and particle filter.
Replacing the Infrared Carbon Dioxide 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 carbon dioxide sensor PCB, then lift
the IR carbon dioxide 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 carbon dioxide sensor PCB.
6. Verify that you are using the correct replacement sensor, then plug the sensor into the IR
carbon dioxide 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” on page 16.
Replacing the Hydrophobic Filter
1. Turn off the controller.
2. Turn off power to the controller.
3. Open the housing door of the sample-draw detector.
4. Disconnect the filter from the rubber elbows on each end of the filter, then remove the filter
from the sample-draw detector.