Ametek Thermox 2000 ATEX Series User Manual page 139

Calibration Setup Checks
Calibration gas check
Check that the correct calibration gas values have been entered into
the control unit. To do this, select the Cal Gas Value menu option
from the Calibrate key on the control unit and check that the cali-
bration gas values entered match the analyzed concentration of the
cylinders.
Check that the calibration gas cylinders are turned on and are not
empty.
Check for the proper flow rate and proper delivery pressure of
calibration gases when the remote calibration unit has been activated
(see the Inject Cal Gas menu option from the Calibrate key chapter
for help on how to do this).
Calibration line check
Ensure that your calibration line is not contaminated with such things as
pipe dope, cutting fluid, oil, or solvents. All these contaminants produce
hydrocarbon vapors that interfere with the proper calibration of your ana-
lyzer. The result of this will be lower than expected oxygen readings. To
test for contaminated lines, you must temporarily bypass your current cali-
bration line with a clean calibration line (directly from cylinder to the sen-
sor calibration inlet port, using a flow meter to set the proper flow) and
compare the response with that from the possibly contaminated line. The
best calibration gas to use for this check is an O zero calibration gas.
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Maintenance and Troubleshooting | 6-11