RKI Instruments Gas Tracer - Manual (Page 40)

32 • Measuring Mode, Normal Operation Gas Tracer Operator’s Manual
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 17: 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 33, to protect the % LEL sensor. Failure to do so will result
in damage to the % LEL sensor.
WARNING: If the combustible channel is set for % volume only, then
there are no gas alarms for any detection channel. See “HC
Range Screen” on page 46.
There are three important issues to keep in mind when monitoring for
combustible
gas.