3-38 | Model 933S UV Analyzer
Sample System Leak Check
The analyzer has been checked at the factory for pressure leaks. However,
fittings can loosen during transport, and the Sample, Vent, and other lines are
installed on-site. Therefore, the entire sample system should be checked for
leaks before any sample gas is introduced into the system for the first time or
following the replacement of any lines/fittings or Measuring Cell parts.
Hazardous Locations
Before proceeding, test the area around the analyzer for explosive
gases and proceed only when the area is found to be safe.
Do not remove the cover of the Explosion-Proof Digital Communica-
tions Port on the front of the Lower Enclosure, do not connect a serial
cable to the Communications Port, do not open the Upper/Lower En-
closures, and do not power up/down the analyzer or computer if there
is an explosive gas atmosphere present.
Preventing leaks in the sample system is critical to ensure proper ana-
lyzer operation. If sample gas migrates into the Optical Bench Assembly
or Reflector Block due to a leak in the Measuring Cell, the optics will
become damaged and most likely require replacement. Most leaks are
preventable with the regular replacement of the Measuring Cell o-rings.
To leak check the sample system:
1. Using the Configurator Software, change the Flow Control setting to ‘0’
(auto). Click OK then Apply. Do not save the changes to EEPROM.
2. If the analyzer uses Measured Pressure Compensation (optional),
change it to Fixed mode so that a “f: Sample gas pressure too low”
alarm does not occur. To do this, view the Cell/Misc Parameters dialog
box and enter a value in the Default Cell Pres (pressure compensation)
field that is the same as, or approximately, the Measuring Cell pressure.
Refer to “Cell/Miscellaneous (Compensation) Parameters” in Chapter 4.
Close the sample inlet valve. Backpurge the analyzer sample system
with Zero gas for 2–3 minutes.
3. Change the Flow Control setting to ‘4’ (shut-in/shut-off). Click OK
then Apply. Do not save the changes to EEPROM.
Bleed down the sample system to atmospheric pressure (check gauge).
To avoid tearing the Membrane Filters in the Filterblock, always bleed
down the sample system pressure on the downstream (outlet) side of
the Filterblock. Pressure differentials of more than 210 KPA (30 PSI)
from the inlet side to the outlet side can tear the Filters and they will
have to be replaced.
!
WARNING
!
CAUTION
!
CAUTION
This procedure
assumes communication with
the analyzer has already been
established.
Setup (tab)
Gas Calibration<<Flow
Control>>
Setup (tab)
Cell/Misc
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