65-2394RK-CH4-4 Combustible Gas Transmitter Operator’s Manual Part Number: 71-0277RK Revision: P1 Released: 4/9/13 RKI Instruments, Inc. www.rkiinstruments.
WARNING Read and understand this instruction manual before operating transmitter. Improper use of the transmitter could result in bodily harm or death. Periodic calibration and maintenance of the transmitter is essential for proper operation and correct readings. Please calibrate and maintain this transmitter regularly! Frequency of calibration depends upon the type of use you have and the sensor types.
Product Warranty RKI Instruments, Inc. warrants gas alarm equipment sold by us to be free from defects in materials, workmanship, and performance for a period of one year from date of shipment from RKI Instruments, Inc. Any parts found defective within that period will be repaired or replaced, at our option, free of charge.
Table of Contents Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Combustible Gas Detector. . . . . . . . . . . . . . . . . .
Overview This manual describes the 65-2394RK-CH4-4 combustible gas transmitter. This manual also describes how to install, start up, configure, maintain, and calibrate the transmitter when it is used with a gas monitoring controller. A parts list at the end of this manual lists replacement parts and accessories for the combustible gas transmitter. Specifications Table 1 lists specifications for the combustible gas transmitter.
Description The 65-2394RK-CH4-4 combustible gas transmitter utilizes an infrared type of detector which has some advantages over a catalytic type of combustible detector. The infrared detector will generally have a longer service life than a catalytic detector, it will require calibration less often, and it can detect combustible gas even if there is no oxygen in the sample which allows detection of combustible gas in an inert atmosphere.
Infrared LEL Detector The infrared LEL detector is made up of a miniature infrared combustible gas LEL detector housed and encapsulated in a pipe nipple. The pipe nipple has 3/4” NPT threads on each end and a 1 1/4” hex that allows removal or installation of the detector with a wrench. A porous flame arrestor that is coated with a hydrophobic film that repels liquids is on one end of the detector and allows sample gas to enter the detector.
CAUTION: The amplifier includes two additional potentiometers. They are factory-set. Do not adjust them. Test Points The test points are on the left side of the amplifier (see Figure 1). The test points produce a 100 mV to 500 mV output that corresponds to the transmitter’s 4 to 20 mA output. Use the test points and a voltmeter to measure the amplifier’s output during the start-up and calibration procedures.
3/4 NPT Female 2.70 .38 3.65 9.00 M AX Rubber Spacer, 3X J-Box I R LEL Detector 5.25 Calibration Cup/Splash Guard .75 Figure 2: Mounting the Combustible Gas Transmitter 2. At the monitoring site you select, hang or mount the detector junction box with the detector facing down (see Figure 2). 3. Install 3/16 inch I.D. flexible polyurethane tubing to the fitting at the bottom of the calibration cup/splash guard and route it to an accessible area that is close to the amplifier junction box.
Wiring the Detector to the Amplifier WARNING: Always verify that the power to the controller is off before you make wiring connections. 1. Confirm that no power is being applied to the amplifier. If the amplifier has already been connected to a controller, turn off the controller and turn off or unplug power to the controller. 2. Remove the detector junction box’s cover from the junction box. 3. Remove the amplifier junction box’s cover from the junction box. 4.
Cable Shield Amplifier PW R / SIG S Detector Terminal Strip R W L EL G B Black Green W hite Red Black Green W hite Red Amplifier J-Box Detector J-Box IR LEL D etector Calibration Cup/Splash G uard Figure 3: Wiring the Detector to the Amplifier 10. Reinstall the detector terminal strip into its socket. 11. If shielded cable is used, connect the cable’s drain wire to an available chassis (earth) ground at the amplifier junction box. The amplifier mounting screw is a convenient grounding location.
3. Remove the amplifier junction box’s cover from the junction box. 4. Guide a three-conductor, shielded cable, or three wires in conduit through the top conduit hub of the amplifier junction box. 5. Pull out the controller terminal strip, and connect the three wires to the terminal strip as follows (see Figure 4). • Connect the positive wire to the PWR/SIG “+” terminal. • Connect the signal wire to the PWR/SIG “S” terminal. • Connect the negative wire to the PWR/SIG “-” terminal.
+ 24 VDC 4 - 20 mA In (S) - (DC Ground) Cable Shield Amplifier J-Box Controller or Recording Device S R W G LEL B PWR / SIG Amplifier (Transmitter) Black Green White Red Detector Wires Figure 4: Wiring the Amplifier to a Controller 10. If shielded cable is used, connect the cable’s drain wire to an available chassis (earth) ground at the controller. RKI controllers typically have a ground stud that can be used to ground the cable’s drain wire.
Start Up This section describes procedures to start up the combustible gas transmitter and place the transmitter into normal operation. Introducing Incoming Power 1. Complete the installation procedures described earlier in this manual. 2. Verify that the power wiring to the controller is correct and secure. Refer to the controller operator’s manual. 3. Turn on power to the controller. 4. Turn on the controller. 5. Verify that the controller is on and operating properly.
6. Turn the regulator’s on/off knob counterclockwise to open it. Gas will begin to flow. 7. Allow the gas to flow for the length of time determined in “Determining Response Time” on page 16. 8. Verify a voltmeter reading of 100 mV (±2 mV). 9. If necessary, use a small flat-blade screwdriver to adjust the zero pot until the voltmeter reading is 100 mV (±2 mV). 10. Turn the regulator’s on/off knob clockwise to close it. 11.
Preparing for the response test 1. Place the controller into its calibration mode or disable external alarms. 2. Verify that the controller display reading for the channel you are testing is 0 %LEL. If the display reading is not 0 %LEL, set the zero reading of the transmitter as described in “Start Up” on page 10, then continue this procedure. 3. Screw the regulator into the calibration cylinder. 4.
Troubleshooting The troubleshooting guide describes symptoms, probable causes, and recommended action for problems you may encounter with the combustible gas transmitter. NOTE: This troubleshooting guide describes transmitter problems only. See the controller operator’s manual for problems you may encounter with the controller. Table 2:Troubleshooting the Combustible Gas Transmitter Condition Symptom(s) Probable Causes Recommended Action Fail Condition • Controller indicates a fail condition.
5. Disconnect the detector leads from the terminal block in the detector junction box. Note the position of the color-coded leads as you remove them. 6. Unscrew the detector from the detector junction box. 7. Guide the detector leads of the replacement detector through the bottom conduit hub of the detector junction box, then screw the mounting threads of the detector into the conduit hub.
leads were removed during this procedure, refer to Table 3 and Table 4 below.
controlled environment where calibration adjustments are minimal at calibration, then a calibration frequency of every 9 to 12 months is adequate. If an application is very demanding, for example if the environment is not well controlled, then more frequent calibration than every 6 months may be necessary.
Preparing for Calibration 1. Unscrew and remove the amplifier junction box’s cover from the junction box. 2. Set a voltmeter to measure in the millivolt (mV) range. 3. Plug the voltmeter leads into the test points on the amplifier. Plug the positive lead into the red (+) test point; plug the negative lead into the black (-) test point. 4. Use the following formula to determine the correct test points output for the calibrating sample.
Returning to Normal Operation 1. Remove the voltmeter leads from the amplifier test points. 2. Disconnect the calibration cup/splash guard’s flexible tubing from the regulator. NOTE: Do not disconnect the flexible tubing from the calibration cup/splash guard. 3. Secure the amplifier junction box cover to the junction box. 4. When the controller display reading falls below the alarm setpoints, return the controller to normal operation. 5.
