Ametek Thermox 2000 ATEX Series User Manual page 143

Process Pressure Checks
To check that you entered the process pressure correctly, select the Process
Pressure menu option from the Setup key. Also ensure that the calibration
process pressure equals normal operating process pressure. Calibration
should only be performed under these conditions for highest accuracy.
Cell Checks
If the cell fails when you first begin to use the analyzer, it is likely that there
is a leak in the sensor plumbing or an improper calibration gas setup, and
there is not a problem with the cell itself (see the "Leak Check" section
later in this chapter for help on how to check for leaks; see the "Calibra-
tion/Aspirator Air Checks" section earlier in this chapter for help on check-
ing your calibration gas setup).
If the analyzer has been operating for some time and you feel the oxygen
reading is inaccurate, first check by running a known calibration gas to
verify the analyzer's response. If the analyzer responds to the calibration
gas correctly, it indicates either leaking or plugged plumbing.
If your analyzer doesn't respond properly to the calibration gas, then it
may indicate a problem with the cell. Before replacing the cell, put the
analyzer through a primary calibration and see if this improves the re-
sponse of the analyzer. If this doesn't work, check for leaks or plugged
plumbing.
If this doesn't solve the problem, replace the cell, then run another pri-
mary calibration.
Maintenance and Troubleshooting | 6-15