Teledyne gfc 7000ta operation manual Predicting Failures Using the Test Functions

Maintenance Model GFC7000TA Carbon Dioxide Analyzer

8.2. 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 (DAS) is a convenient way to record and track these changes. Use APICOM to download and review this data from a remote location.

Table 8-3: Predictive uses for Test Functions

FUNCTION	CONDITION	BEHAVIOR	INTERPRETATION
STABILITY	Zero Cal	Increasing	Pneumatic Leaks – instrument & sample system
			Detector deteriorating
			Source Aging
CO2 MEAS	Zero Cal	Decreasing	Detector deteriorating
			Optics getting dirty or contaminated
			Source Aging
		Increasing	Detector deteriorating
			Contaminated zero gas (H2O)
	Zero Cal		Source Aging
			Detector deteriorating
		Decreasing	GFC Wheel Leaking
MR RATIO			Pneumatic Leaks
			Contaminated zero gas (CO2)
			Source Aging
		Increasing	Pneumatic Leaks – instrument & sample system
	Span Cal		Calibration system deteriorating
			Source Aging
		Decreasing	GFC Wheel Leaking
			Calibration system deteriorating
		Increasing > 1”	Pneumatic Leak between sample inlet and Sample Cell
			Change in sampling manifold
PRES	Sample		Dirty particulate filter
			Pneumatic obstruction between sample inlet and Sample
		Decreasing > 1”
			Cell
			Obstruction in sampling manifold
	Any, but with		Mechanical Connection between IR-Detector and Sample
PHT DRIVE	Bench Temp at	Increasing	Cell deteriorating
	48°C		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

Teledyne Analytical Instruments 183