12 • 35-3001-01H-DIL Hydrogen Sample-Draw Detector
operation. If the display reading is not 0 %LEL, continue with step 3.
3. Perform a zero operation at the controller. See “Setting the Zero Reading” on page 18 and the
controller operator’s manual for instructions to perform a zero operation.
4. If necessary, reinstall the sample line to the inlet fitting or put the end of the sample line back
in the sample location.
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 0.8 SCFH. If necessary use the
sensor flow control valve to adjust the flow rate to 0.8 SCFH. Turn the valve’s knob clockwise
to increase the flow and counterclockwise to decrease the flow.
3. At the controller, verify a display reading of 0 %LEL. 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
1. Draw sample from a fresh air environment and 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.
Performing the response test
1. Screw the fixed flow regulator into the hydrogen calibration cylinder.
2. Attach the gas bag tubing to the regulator on the hydrogen calibration cylinder.
