RKI Instruments 35-3001A-05-02 - Manual (Page 17)

35-3001A-05-02 Carbon Dioxide Sample-Draw Detector • 13
(+) test point; plug the negative lead into the black (-) test point.
4. Screw the demand flow regulator into the 100% nitrogen calibration cylinder.
5. Connect the calibration tubing from the demand flow regulator to the inlet fitting. Gas will
begin to flow.
6. Allow the sample-draw detector to draw sample for one minute.
7. Verify a voltmeter reading of 100 mV (± 2 mV).
8. If necessary, use a small flat-blade screwdriver to adjust the zero potentiometer until the
voltmeter reading is 100 mV (± 2 mV).
9. Remove the calibration tubing from the inlet fitting, then reconnect the sample tubing to the
inlet fitting.
10. Remove the voltmeter leads from the test points.
11. 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, and adjust the low flow setting.
Preventive Maintenance
This section describes a preventive maintenance schedule to ensure the optimum performance of
the sample-draw detector. It includes daily, monthly, 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 depending on location.
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.