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Model 9110T NOx Analyzer Instrument Maintenance
Teledyne Analytical Instruments 240
Table 11-1: 9110T Maintenance Schedule
ITEM ACTION FREQ
CAL
CHECK
REQ’D
DATE PERFORMED
TEST
functions
Review and
evaluate
Weekly No
Particulate
filter
Change
particle filter
Weekly No
Zero/span
check
Evaluate
offset and
slope
Weekly No
Zero/span
calibration
Zero and
span
calibration
Every 3 months Yes
External zero
air scrubber
option
Exchange
chemical
Every 3 months No
External
dryer option
Replace
chemical
When indicator
color changes
No
Ozone
cleanser
Change
chemical
Annually Yes
Reaction cell
window
(“optical
filter” in
Figure 11-6)
Clean Annually or as
necessary
Yes
DFU filters Change
particle filter
Annually No
Pneumatic
sub-system
Check for
leaks in gas
flow paths
Annually or
after repairs
involving
pneumatics
Yes if a
leak is
repaired
Reaction cell
O-rings &
sintered
filters
Replace Annually
Yes
PMT Sensor
Hardware
Calibration
Low-level
hardware
calibration
On PMT/
preamp
changes or if
slope is outside
of 1.0±0.3
Yes
Pump Rebuild head when RCEL
pressure
exceeds 10 in-
Hg-A (at sea
level)
Yes
Inline
Exhaust
Scrubber
Replace Annually No
NO
2
converter
Replace
converter
Every 3 years
or if conversion
efficiency drops
below 96%
Yes
Desiccant
bags
Replace Any time PMT
housing is
opened for
maintenance
n/a