RKI Instruments 65-2400RK - Manual (Page 13)

65-2400RK Combustible Gas Transmitter • 9
Maintenance
This section describes maintenance procedures. It includes preventive maintenance,
troubleshooting, and component replacement procedures.
Preventive Maintenance
This section describes a preventive maintenance schedule to ensure the optimum
performance of the combustible gas transmitter. It includes daily, monthly, and quarterly
procedures.
Daily
Verify a display reading of 0%LEL at the controller. Investigate significant changes in the
display reading.
Monthly
This procedure describes a test to verify that the combustible gas transmitter responds
properly to the target gas. It describes the test using a calibration kit that includes a
calibration cup, calibration gas, sample tubing, and a fixed flow regulator with an on/off
knob. RKI Instruments, Inc. recommends using a 0.5 LPM (liters per minute) fixed flow
regulator.
NOTE: Performing a response test on the combustible transmitter may cause alarms. Be
sure to put the controller into its calibration program or disable external alarms
before performing this test.
Preparing for the response test
1. Place the controller into its calibration program 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 zero, set the zero reading of the transmitter as described
in “Start Up” on page 8 of this manual, then continue this procedure.
3. Screw the calibration cup onto the bottom of the combustible detector.
4. Screw the regulator into the calibration cylinder.
5. Use the calibration kit sample tubing to connect the regulator to the calibration cup.
6. Set a voltmeter to measure in the millivolt (mV) range.
7. Remove the junction box cover, then plug the voltmeter leads into the test points on
the amplifier.
Plug the positive lead into the test point labeled TP+; plug the negative lead into the
test point labeled TP-.
8. Use the following formula to determine the correct test points output for the test
sample.
Output (mV) = (calibrating sample/fullscale) X 400 + 100
For example, with a test sample of 50% LEL and a fullscale setting of 100% LEL, the
correct output is 300 mV.
300 (mV) = (50/100) X 400 +100
Performing the response test
1. Turn the regulator’s on/off knob counterclockwise to open it. The sample gas will