Gas Tracer Operator’s Manual, CSA Version
Measuring Mode, Normal Operation • 35
Using the Dilution Fitting
The external dilution fitting is a 1:1 dilution fitting. It is normally used when it is
necessary to introduce air into a sample that has no oxygen or a very low level of
oxygen, such as a nitrogen purged sample. It can also be used when one of the
target gas levels in the sample area will likely be present in a concentration above
the detection range for that gas. Since the fittings partially consist of unplated
brass, they are not appropriate for detection of elevated levels of H
2
S.
1. Start up the Gas Tracer as described in “Start Up, Normal Mode” on page 25.
2. Install the dilution fitting to the Gas Tracer’s quick connect inlet fitting.
3. Connect the tapered rubber nozzle or the sample hose to the Gas Tracer’s
quick connect inlet fitting.
4. If a sample hose is used, screw the probe onto the sample hose’s threaded
fitting.
5. Monitor the sampling area.
NOTE:
The Gas Tracer can be calibrated either with or without the dilution
fitting in place. If calibrated without the dilution fitting in place, then
display readings must be doubled to determine the actual gas
concentration. If calibrated with the dilution fitting in place, then a
sample bag must be used during calibration, and the display readings
will be the actual gas concentrations.
CAUTION:
If the dilution fitting is in place for calibration, do not use a demand flow
regulator. Use a sample bag. The use of a demand flow regulator with a
dilution fitting when calibrating will result in an inaccurate calibration.
Figure 18: Dilution Fitting
Combustible Gas Detection
The Gas Tracer can support two combustible gas sensors, a TC (thermal
conductivity) sensor for detection in the % volume range, and a catalytic sensor
for detection in the % LEL range. Either or both sensors may be installed in your
unit.
If both the % volume and % LEL sensors are installed, the combustible gas
channel is setup at the factory as % LEL/% volume autoranging. In this case, the
combustible gas channel will display the combustible gas concentration in % LEL
up to 100% LEL. If the combustible gas concentration rises above 100% LEL, then
the unit automatically begins displaying the concentration in % volume.
CAUTION:
If both combustible sensors are installed in your instrument, make sure you
follow the recommendations in the next section, “Applications with High
Levels of Combustible Gas” on page 36, to protect the % LEL sensor.
Failure to do so will result in damage to the % LEL sensor.
