Teledyne 9110EH - Nitrogen Oxides Analyzer - Manual (Page 161)

Model 9110EH Instruction Manual Instrument Maintenance
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 M9110EH Final Test and
Validation Data Form attached to the manual). Table 9-2 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. APICOM
control software can be used (Section 6.11.5 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 9110EH.
M9110EH Rev 0 147