22 • 35-3001A-09 Oxygen/Hydrogen Sulfide Sample-Draw Detector
2. Allow the sample draw detector to draw sample for one minute.
3. Verify a voltmeter reading of 434 mV (± 2 mV).
4. If necessary, use a small flat-blade screwdriver to adjust the span potentiometer until the
voltmeter reading is 434 mV (± 2 mV). If you used a zero air calibration cylinder to set the
zero reading, proceed to step 5. If you verified a fresh air environment, proceed to the next
section, Setting the Zero Reading.
5. Disconnect the sample tubing from the inlet fitting.
6. Unscrew the regulator from the zero air calibration cylinder.
Setting the Zero Reading
1. Screw the demand flow regulator onto the 100% N
2
calibration cylinder.
NOTE:
If you do not want to keep two calibration cylinders, 100% N
2
and 25 ppm H
2
S in
nitrogen, you may use the 25 ppm H
2
S in nitrogen to zero the oxygen sensor.
2. Connect the sample tubing from the regulator to the inlet line.
3. Allow the sample-draw detector to draw the calibrating sample for 1 minute.
4. Verify a voltmeter reading of 100 mV (± 2 mV).
5. If necessary, use the zero potentiometer on the amplifier to adjust the reading to 100 mV (± 2
mV).
6. Disconnect the sample tubing from the sample-draw detector’s inlet fitting.
7. Reconnect the incoming sample line to the inlet fitting.
8. Unscrew the regulator from the calibration cylinder.
Returning to Normal Operation
1. Wait 1 to 2 minutes to allow the oxygen reading at the controller to return to normal, then
return the controller to normal operation.
NOTE:
If you do not allow the oxygen reading to return to normal, then unwanted alarms may
occur.
2. Remove the voltmeter leads from the amplifier test points.
3. Close the housing door.
4. Verify that the controller display reading stabilizes at 20.9%.
5. Store the components of the calibration kit in a safe and convenient place.
