Teledyne GFC 7001E, GFC 7001EM 12.2. PREDICTING FAILURES USING THE TEST FUNCTIONS

Maintenance Model GFC7001E Carbon Dioxide Analyzer
Teledyne Analytical Instruments 263
12.2. PREDICTING FAILURES USING THE TEST FUNCTIONS
The Test Functions can be used to predict failures by looking at how their values change over time. Initially it
may be useful to compare the state of these Test Functions to the values recorded on the printed record of the
final calibration performed on your instrument at the factory, P/N 04307. Table 12-3 can be used as a basis for
taking action as these values change with time. The internal data acquisition system (iDAS) is a convenient way
to record and track these changes. Use APICOM to download and review this data from a remote location.
Table 12-3: Predictive uses for Test Functions
FUNCTION CONDITION BEHAVIOR INTERPRETATION
STABILITY Zero Cal Increasing  Pneumatic Leaks – instrument & sample system
 Detector deteriorating
CO MEAS Zero Cal Decreasing
 Source Aging
 Detector deteriorating
 Optics getting dirty or contaminate d
MR RATIO
Zero Cal
Increasing
 Source Aging
 Detector deteriorating
 Contaminated zero gas (H2O)
Decreasing
 Source Aging
 Detector deteriorating
 GFC Wheel Leakin g
 Pneumatic Leaks
 Contaminated zero gas (CO)
Span Cal
Increasing
 Source Aging
 Pneumatic Leaks – instrument & sample system
 Calibration s ystem deteriorating
 GFC Wheel Leakin g
Decreasing  Source Aging
 Calibration s ystem deteriorating
PRES Sample
Increasing > 1”  Pneumatic Lea k between sample inlet and Sample Cell
 Change in sam pling manifold
Decreasing > 1”
 Dirty particulate filter
 Pneumatic obstruction bet ween sample inlet and
Sample Cell
 Obstruction in sampling manif old
PHT DRIVE
Any, but with
Bench Temp at
48°C
Increasing
 Mechanical Connecti on between IR-Detector and
Sample Cell deteriorating
 IR-Photodetector deteriorating
OFFSET Zero Cal
Increasing  See MR Ratio - Zero Cal Decreasing above
Decreasing  See MR Ratio - Zero Cal Increasing above
SLOPE Span Cal
Increasing  See MR Ratio - Span Cal Decreasing above
Decreasing  See MR Ratio – Span Cal Increasing above