MAINTENANCE SCHEDULE & PROCEDURES Model 360E Instruction Manual
9.2. 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 9-3 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 9-3: Predictive uses for Test Functions
FUNCTION CONDITION BEHAVIOR INTERPRETATION
STABILITY Zero Cal Increasing Pneumatic Leaks – instrument & sample system
Detector deteriorating
CO2 MEAS Zero Cal Decreasing
Source Aging
Detector deteriorating
Optics getting dirty or contaminated
Increasing
Source Aging
Detector deteriorating
Contaminated zero gas (H2O)
Zero Cal
Decreasing
Source Aging
Detector deteriorating
GFC Wheel Leaking
Pneumatic Leaks
Contaminated zero gas (CO2)
Increasing
Source Aging
Pneumatic Leaks – instrument & sample system
Calibration system deteriorating
MR RATIO
Span Cal
Decreasing
Source Aging
GFC Wheel Leaking
Calibration system deteriorating
Increasing > 1” Pneumatic Leak between sample inlet and Sample Cell
Change in sampling manifold
PRES Sample
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
Increasing See MR Ratio - Zero Cal Decreasing above
OFFSET Zero Cal Decreasing See MR Ratio - Zero Cal Increasing above
Increasing See MR Ratio - Span Cal Decreasing above
SLOPE Span Cal Decreasing See MR Ratio – Span Cal Increasing above
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