35-3001A-09 Oxygen/Hydrogen Sulfide Sample-Draw Detector • 13
3. Set a voltmeter to measure in the millivolt (mV) range.
4. Plug the voltmeter leads into the test points on the oxygen amplifier. Plug the positive lead into
the red (+) test point; plug the negative lead into the black (-) test point.
5. Verify a voltmeter reading of 434 mV (± 2 mV).
6. If necessary, use a small flat-blade screwdriver to adjust the span potentiometer until the
voltmeter reading is 434 mV (± 2 mV).
7. Remove the voltmeter leads from the oxygen amplifier’s test points.
8. Plug the voltmeter leads into the test points on the H
2
S amplifier. Plug the positive lead into the
red (+) test point; plug the negative lead into the black (-) test point.
9. Verify a voltmeter reading of 100 mV (± 2 mV).
10. If necessary, use a small flat-blade screwdriver to adjust the zero potentiometer until the
voltmeter reading is 100 mV (± 2 mV).
11. Remove the voltmeter leads from the H
2
S amplifier’s test points.
12. Close the housing door.
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, monthly, and quarterly 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. Verify a display reading of 20.9% for the oxygen channel and 0 ppm for the H
2
S channel at the
controller. Investigate significant changes in the display reading.
Monthly Response Test
This procedure describes a test to verify that the sample-draw detector responds properly to the
target gas.
NOTE:
To reduce the response time of this test, use a short incoming sample line. If the sample-
draw detector’s sample line is long, connect a shorter line for this test. Make sure you
reconnect the sample line after you complete this procedure.
NOTE:
Performing a response test on the sample-draw detector may cause alarms. Be sure to put
the controller into its calibration program or disable external alarms before performing
this test.
