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Teledyne API - Model 200EH/EM Operation Manual Instrument Maintenance
177
9.2. PREDICTIVE DIAGNOSTICS
The analyzer’s test functions can be used to predict failures by looking at trends in their values. Initially it may
be useful to compare the state of these test functions to the values measured on your instrument at the factory
and recorded on the M200EH/EM Final Test and Validation Data Form (Teledyne Instruments part number
04490, attached to the manual). Table 9-2 can be used as a basis for taking action as these values change with
time. The internal d
ata acquisition system (iDAS) is
a convenient way to record and track these changes.
APICOM control software can be used to download and review these data even from remote locations (Section
6.15.2.8 describes APICOM).
Table 9-2: Predictive Uses for Test Functions
FUNCTION EXPECTED ACTUAL INTERPRETATION & ACTION
Fluctuating Developing leak in pneumatic system. Check for leaks
RCEL
pressure
Constant to
within ± 0.5
Slowly increasing
Pump performance is degrading. Replace pump head
when pressure is above 10 in-Hg-A
Fluctuating Developing leak in pneumatic system. Check for leaks
Slowly increasing Flow path is clogging up. Replace orifice filters
SAMPLE
pressure
Constant within
atmospheric
changes
Slowly decreasing
Developing leak in pneumatic system to vacuum
(developing valve failure). Check for leaks
Ozone Flow
Constant to
within ± 15
Slowly decreasing Flow path is clogging up. Replace orifice filters
Developing AZERO valve failure. Replace valve
PMT cooler failure. Check cooler, circuit, and power
supplies
Developing light leak. Leak check.
AZERO
Constant within
±20 of check-out
value
Significantly
increasing
O
3
air filter cartridge is exhausted. Change chemical
NO2 CONC
Constant for
constant
concentrations
Slowly decreasing
signal for same
concentration
Converter efficiency may be degrading. Replace
converter.
Change in instrument response. Low level (hardware)
calibrate the sensor
NO2 CONC
(IZS)
Constant
response from
day to day
Decreasing over time
Degradation of IZS permeation tube. Change
permeation tube
NO2 CONC
(IZS)
Constant
response from
day to day
Heavily fluctuating
from day to day
Ambient changes in moisture are affecting the
performance. Add a dryer to the zero air inlet.
NO CONC
Constant for
constant
concentration
Decreasing over time
Drift of instrument response; clean RCEL window,
change O
3
air filter chemical.
9.3. MAINTENANCE PROCEDURES
The following procedures need to be performed regularly as part of the standard maintenance of the Model
200EH/EM.
04521C (DCN5731)