Teledyne GFC-7001E - Trace CO Analyzer - Manual (Page 263)

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 contaminated
MR RATIO
Zero Cal
Increasing
 Source Aging
 Detector deteriorating
 Contaminated zero gas (H
2
O)
Decreasing
 Source Aging
 Detector deteriorating
 GFC Wheel Leaking
 Pneumatic Leaks
 Contaminated zero gas (CO)
Span Cal
Increasing
 Source Aging
 Pneumatic Leaks – instrument & sample system
 Calibration system deteriorating
 GFC Wheel Leaking
Decreasing
 Source Aging
 Calibration system deteriorating
PRES Sample
Increasing > 1”
 Pneumatic Leak between sample inlet and Sample Cell
 Change in sampling manifold
Decreasing > 1”
 Dirty particulate filter
 Pneumatic obstruction between sample inlet and
Sample Cell
 Obstruction in sampling manifold
PHT DRIVE
Any, but with
Bench Temp at
48°C
Increasing
 Mechanical Connection 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