16 • 35-3001A-07-03 Methane/Hydrogen Sulfide Sample-Draw Detector
Recommended action
1. Verify that the calibration cylinder contains an adequate supply of a fresh test sample.
2. If a demand flow regulator calibration kit is used, use a different demand 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. If the calibration/response difficulties continue, replace the sensor as described later in this
section.
6. 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 IR CH
4
sensor, IR CH
4
amplifier, hydrogen sulfide
sensor, hydrogen sulfide amplifier, hydrophobic filter, and particle filter.
Replacing the IR CH
4
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 four screws that secure the IR CH
4
sensor PCB, then lift the IR CH
4
sensor PCB and sensor off of the flow block.
There is a gasket at the bottom of the flow block. Be sure the gasket stays in place.
5. Unplug the sensor from the IR CH
4
sensor PCB.
6. Verify that you are using the correct replacement sensor, then plug the sensor into the IR CH
4
sensor PCB.
7. Place the sensor and sensor PCB in the IR CH
4
sensor cavity.
8. Secure the sensor PCB on the flow block with the four 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 5 minutes before you continue.
12. Calibrate the replacement sensor as described in “Calibration, IR CH
Replacing the IR CH
4
Amplifier
1. Turn off the controller.
2. Turn off power to the controller.
3. Open the housing door of the sample-draw detector.
4. Remove the detector and controller plug-in terminal strips by grasping the sides of the strips
with your fingers. Let the terminal strips hang by their connected wires while you replace the
amplifier.
5. Unscrew the screw in the lower left corner of the amplifier and remove the screw, lock washer,
and flat washer. Be careful not to lose any of these parts.
