14 • 35-3001-01H-DIL Hydrogen Sample-Draw Detector
4. Verify that the sensor wiring is correct and secure. “Wiring the Sample-Draw Detector to a
Controller” on page 9 describes sensor wiring connections.
5. Calibrate the sample-draw detector as described in “Calibration” on page 18.
6. If the fail condition continues, replace the sensor as described in “Replacing Components of
the Sample-Draw Detector” on page 14.
7. If the fail condition continues, contact RKI Instruments, Inc. for further instruction.
Slow or No Response/Difficult or Unable to Calibrate
Symptoms
•
The sensor responds slowly or does not respond during the monthly response test.
•
Unable to accurately set the zero or response reading during the calibration procedure.
•
The sensor requires frequent calibration.
Probable causes
•
The calibration cylinder is low, out-dated, or defective.
•
The fixed flow regulator is not functioning properly.
•
The sample-draw detector’s flow rate is too low because of an obstructed sample line, failed
pump, etc.
•
The dilution fitting is blocked.
•
The sample-draw detector is malfunctioning.
Recommended action
1. Verify that the calibration cylinder contains an adequate supply of a fresh test sample.
2. Use a different fixed flow regulator to determine if the original one is functioning properly.
3. If necessary, set the correct flow rate with the sensor flow control valve.
4. If you cannot set the correct flow rate, check the sample line for obstructions or kinks.
5. Check the dilution fitting for obstructions.
6. If the calibration/response difficulties continue, replace the sensor as described later in this
section.
7. If the calibration/response difficulties continue, contact RKI Instruments, Inc. for further
instruction.
Replacing Components of the Sample-Draw Detector
This section includes procedures to replace the hydrogen sensor, hydrophobic filter, and particle
filter.
Replacing the Hydrogen Sensor
1. Turn off the controller.
2. Turn off power to the controller.
3. Open the housing door of the sample-draw detector.
4. Unscrew and remove the two screws that secure the sensor retaining plate, then lift the plate,
connector, and sensor out of the housing.
5. Unplug the connector from the sensor.
6. Verify that you are using the correct replacement sensor (NC-6244A is printed on the sensor),
then plug the sensor into the connector.
7. Place the sensor in the hydrogen sensor cavity, then position the retaining plate on the two
