Maintenance and Troubleshooting | 6-11
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 calibration gas
values entered match the analyzed concentration of the cylinders.
Check that the calibration gas cylinders are turned on and are not
empty. In addition, ensure that the calibration gas bottle pressure has
at least 500 lb. of pressure.
Check for the proper flow rate and proper delivery pressure of calibra-
tion gases when the remote calibration unit has been activated (see the
inject Cal Gas menu option from the Calibration chapter for help on
how to set up flow and inlet pressure).
Check that the PPM calibration gas cylinders are made of aluminum
and not steel.
Check that the calibration gas cylinders are less than two years old.
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 leading to lower-than-expected oxygen readings. To test for contami-
nated lines, you must temporarily bypass your current calibration line
with a clean calibration line (directly from the calibration gas cylinder to
the sensor 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 O
2
zero calibration gas.
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