RKI Instruments 35-3001A-01-02 - Manual (Page 19)

35-3001A-01-02 Combustible Gas Sample-Draw Detector • 15
4. Calibrate the sample-draw detector as described in “Calibration” on page 18.
5. If the fail condition continues, replace the sensor as described in “Replacing the Infrared HC
Sensor” on page 15.
6. 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.
• If a demand flow regulator calibration kit is used, the demand 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 sample-draw detector is malfunctioning.
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 Combustible Gas
Sample-Draw Detector
This section includes procedures to replace the sensor, hydrophobic filter, and particle filter.
Replacing the Infrared HC 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 HC sensor PCB, then lift the IR HC
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 HC sensor PCB.
6. Verify that you are using the correct replacement sensor, then plug the sensor into the IR HC
sensor PCB.
7. Place the sensor and sensor PCB in the IR HC sensor cavity.
8. Secure the sensor PCB on the flow block with the screws you removed in step 4.