12 • 35-3001A-01H Hydrogen Sample-Draw Detector
6. If necessary, use a small flat-blade screwdriver to adjust the zero potentiometer until the
voltmeter reading is 100 mV (± 2 mV).
7. Remove the voltmeter leads from the test points.
8. 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
counterclockwise to increase the flow and clockwise to decrease the flow.
3. Verify a display reading of 0 %LEL at the controller or a reading of 100 mV at the amplifier
test points. 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.
Preparing for the response test
NOTE:
This procedure describes the RKI calibration kit that includes a demand flow regulator.
1. Verify that the display reading at the controller is 0 % LEL.
If the display reading is not 0 % LEL, set the zero reading as described in “Calibration” on
page 18, then continue this procedure.
2. Set a voltmeter to measure in the millivolt (mV) range.
3. Open the housing door, then plug the voltmeter leads into the test points on the amplifier.
Plug the positive lead into the red (+) test point; plug the negative lead into the black (-) test
point.
