Teledyne 9110T Predictive Diagnostics, Maintenance Procedures, Predictive Uses for Test Functions

Model 9110T NOx Analyzer Instrument Maintenance

11.2. PREDICTIVE DIAGNOSTICS

Predictive diagnostic functions including failure warnings and alarms built into the analyzer’s firmware allow the user to determine when repairs are necessary.

The Test Functions can also 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 Test and Validation Data Sheet, P/N 04490.

The following table 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 (Section 8.1.1) to download and review this data from a remote location.

Table 11-2: Predictive Uses for Test Functions

FUNCTION	EXPECTED	ACTUAL	INTERPRETATION & ACTION
RCEL	Constant to within	Fluctuating	Developing leak in pneumatic system. Check for leaks.
			Pump performance is degrading. Rebuild pump when pressure
(pressure)	± 0.5 in-Hg-A	Slowly increasing
			is above 10 in-Hg-A.
	Constant within	Fluctuating	Developing leak in pneumatic system. Check for leaks.
SAMP		Slowly increasing	Flow path is clogging up. Replace orifice filters.
(pressure)	atmospheric
	changes	Slowly decreasing	Developing leak in pneumatic system to vacuum (developing
			valve failure). Check for leaks.
OZONE FL	Constant to within	Slowly decreasing	Flow path is clogging up. Replace orifice filters.
	± 15
			Developing AZERO valve failure. Replace valve.
	Constant within
AZERO		Significantly increasing	PMT cooler failure. Check cooler, circuit, and power supplies.
	±20 of check-out
			Developing light leak.
	value
			O3 air filter cartridge is exhausted. Change chemical.
NO2	Constant for	Slowly decreasing	Converter efficiency may be degrading. Replace converter
	constant	signal for same
(Concentration)			components.
	concentrations	concentration
NO2			Change in instrument response. Low level (hardware) calibrate
	Constant	Decreasing over time	the sensor.
with IZS Option
	response from day		Degradation of IZS permeation tube. Change permeation tube.
installed
	to day
		Heavily fluctuating from	Ambient changes in moisture are affecting the performance.
(Concentration)
		day to day	Add a dryer to the zero air inlet.
NO	Constant for		Drift of instrument response; clean RCEL window. Check for
	constant	Decreasing over time
(Concentration)			flow leaks or irregularities.
	concentration

Note It is recommended that the above functions be checked weekly.

11.3. MAINTENANCE PROCEDURES

The following procedures are to be performed periodically as part of the standard maintenance of the 9110T.

Teledyne Analytical Instruments 241