35-3001-05-XX CO
2
Sample-Draw Detector • 15
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 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 counterclockwise to
increase the flow and clockwise to decrease the flow.
3. 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.
Biannual Calibration
Calibrate the sample-draw detector as described in “Calibration” on page 20.
Troubleshooting
The troubleshooting guide describes symptoms, probable causes, and recommended action for problems you
may encounter with the sample-draw detector.
NOTE:
This troubleshooting guide describes sample-draw detector problems only. See the controller
Operator’s Manual if the controller exhibits any problems.
Fail Condition
Symptoms
•
The sample-draw detector’s Fail LED is on.
•
The monitoring device is operating properly but indicates a reading well below zero.
Probable causes
•
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.
•
The sensor wiring is disconnected or misconnected.
Recommended action
1. At the sample-draw detector, set the correct flow rate with the sensor flow control valve.
2. If you cannot set the correct flow rate, check the sample lines for obstructions or kinks.
3. Verify that the sensor wiring is correct and secure. “Wiring the Carbon Dioxide Sample-Draw Detector
to a Controller” on page 12 describes sensor wiring connections.
4. Calibrate the sample-draw detector as described in “Calibration” on page 20.
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