RKI Instruments 65-2400RK-05 - Manual (Page 9)

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
1. 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.
NOTE: Verifying the response of the transmitter may cause alarms. Be sure to put the
controller into calibration mode or disable external alarms before verification.
Preparing for the response test
1. Verify that the display reading is 0.
If the display reading is not zero, set the zero reading as described in the Start Up
section of this insert, then continue this procedure.
2. Assemble the calibration kit as described in the Calibration section of this insert.
NOTE: Do not screw the regulator into the calibration cylinder at this time.
3. Set a voltmeter to measure in the millivolt (mV) range.
4. 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- .
5. 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