18 • 35-3001A-01-03 Methane Sample-Draw Detector
If you do lose the O-ring or if it is damaged, see “Parts List” on page 20 for the spare part
number.
3. Push the tubing stub up and out of the front ferrule being careful not to lose the ferrule set. If
you do lose the ferrule set or if it is damaged, see “Parts List” on page 20 for the spare part
numbers.
4. Push the new tubing up through the inlet fitting tube nut and replace the ferrule set and the O-
ring, if it came out, in the orientation shown in Figure 6.
5. Screw the inlet fitting tube nut back onto the fitting body. See “Connecting the Sample Lines to
the Sample-Draw Detector” on page 8 for instructions to install a new piece of tubing into the
fitting.
Calibration Frequency
Although there is no particular calibration frequency that is correct for all applications, a calibration
frequency of every 6 months is adequate for most infrared combustible gas sample draw
applications. Unless experience in a particular application dictates otherwise, RKI Instruments, Inc.
recommends a calibration frequency of every 6 months.
If an application is not very demanding, for example detection in a clean, temperature 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.
Calibration
This section describes how to calibrate the methane sample-draw detector. It includes procedures to
prepare for calibration, set the zero reading, set the response reading, and return to normal
operation.
NOTE:
This procedure describes calibration using a demand flow regulator.
Preparing for Calibration
1. Follow the instructions in the controller’s operator’s manual for entering calibration mode.
NOTE:
If you can verify a fresh air environment, it is not necessary to use the zero air calibration
cylinder to set the zero reading.
2. Screw the regulator into a zero air calibration cylinder.
3. Open the housing door.
4. Set a voltmeter to measure in the millivolt (mV) range.
5. Plug the positive lead into the red (+) amplifier test point; plug the negative lead into the black
(-) amplifier test point labeled.
