RKI Instruments 35-3000RK-LEL - Manual (Page 16)

16 • 35-3000RK-LEL Combustible Gas Sample-Draw Detector
6. If the calibration/response difficulties continue, contact RKI Instruments, Inc., for
further instruction.
Replacing Components of the Combustible Gas
Sample-draw Detector
This section includes procedures to replace the sensor, hydrophobic filter, and ferrules.
Replacing the combustible gas 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 retraining 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-6240 is printed on the
sensor), then plug the sensor into the connector.
7. Place the sensor in the combustible gas sensor cavity, then position the retaining plate
on the two standoffs.
8. Secure the retaining plate to the standoffs with the two screws you removed in step 4.
9. Close and latch the housing door.
10. Turn on power to the controller.
11. Turn on the controller.
CAUTION: Allow the replacement sensor to warm up for 15 minutes before you continue.
12. Calibrate the replacement sensor as described in “Calibration” on page 18.
Replacing the filter
1. Open the housing door of the sample-draw detector.
2. Disconnect the filter from the rubber elbows on each end of the filter, then remove the
filter from the sample-draw detector.
3. Install the new filter.
4. Verify that the flow rate is approximately 1.5 SCFH, then close the housing door.
Replacing the ferrules
The INLET and EXHAUST fittings each includes two ferrules that seal the inlet or exhaust
tubing to the fitting. Replace the ferrules if the seal is bad or if you replace the sample
tubing. Always replace the ferrules as a pair.
1. Unscrew the nut that holds the tubing to the fitting from the fitting.
2. Slide the nut away from the end of the tubing.
3. Cut off the end of the sample tube with the old ferrules off about one inch from the
end
4. Slide the nut off the sample tubing.
5. Position the nut so the threaded end is facing you, then insert the bottom (smaller)
ferrule into the nut. Insert the ferrule so the flat side is facing down.