16 • 35-3001-13-02 Carbon Dioxide/Oxygen Sample-Draw Detector
5. Screw the demand flow regulator into the 100% nitrogen calibration cylinder.
6. Connect the calibration tubing from the demand flow regulator to the inlet fitting. Gas will begin to flow.
7. Allow the detector to draw sample for one minute.
8. Verify a reading of 0 ppm or 0% vol for the carbon dioxide channel on the controller display.
9. If the display reading is 0 ppm or 0% vol for the carbon dioxide channel, start up is complete. The sample-
draw detector is in normal operation. If the display reading is not 0 ppm or 0% vol, continue with step 5.
10. Perform a zero operation at the controller. See “Setting the Zero Reading” on page 21 and the controller
operator’s manual for instructions to perform a zero operation.
11. Remove the calibration tubing from the inlet fitting, then reconnect the sample tubing to the inlet fitting.
Maintenance
This section describes maintenance procedures. It includes preventive maintenance procedures. This section also
includes procedures to troubleshoot the sample-draw detector, replace components of the sample-draw detector,
adjust the low flow setting, and remove the particle filter’s tubing stub.
Preventive Maintenance
This section describes a preventive maintenance schedule to ensure the optimum performance of the sample-
draw detector. It includes daily, quarterly, and biannual procedures.
Daily Visual Checks
1. Verify that the Pilot LED is on.
2. Verify that the flowmeter indicates a flow rate of approximately 1.0 SCFH. If necessary use the sensor flow
control valve to adjust the flow rate to 1.0 SCFH. Turn the valve’s knob clockwise to increase the flow and
counterclockwise to decrease the flow.
3. For the carbon dioxide channel: Verify a display reading at the controller of the background concentration of
CO
2
. Typical background concentrations of CO
2
vary from about 300 to 600 ppm (0.03 - 0.06% volume)
depending on location. The 0 - 5,000 ppm and 0 - 5% volume ranges will show a reading in fresh air. The
0 - 50% and 0 - 100% volume ranges should not show a reading in fresh air. Investigate significant changes
in the display reading.
4. For the oxygen channel: Verify a display reading of 20.9% at the controller. Investigate significant changes
in the display reading.
Quarterly Calibration
Calibrate the oxygen sensor as described in “Calibration, Oxygen Sensor” on page 22.
Biannual Calibration
Calibrate the IR CO
2
sensor as described in “Calibration, IR CO
