18 • 35-3001A-01H Hydrogen Sample-Draw Detector
CAUTION:
Do not pull the tubing stub downward to remove it.
1. Remove the particle filter from its tubing stub.
2. Unscrew the outside inlet fitting tube nut from the fitting body. The tubing stub should come
out with the tube nut. Be careful not to lose the O-ring that may come out with the tubing stub.
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 sample draw detector
applications, a calibration frequency of every 3 to 6 months is adequate for most applications.
Unless experience in a particular application dictates otherwise, RKI Instruments, Inc. recommends
a calibration frequency of every 3 months.
If an application is not very demanding, for example detection in a clean, temperature controlled
environment where combustible gases are not normally present and calibration adjustments are
minimal at calibration, then a calibration frequency of every 6 months is adequate.
If an application is very demanding, for example if combustible gases are present often and in
significant concentrations or the environment is not well controlled, then more frequent calibration
than every 3 months may be necessary.
Calibration
This section describes how to calibrate the hydrogen 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.
