R
OUTINE
S
ERVICING
6-4
October 1999 Rosemount Analytical 748250-L
Model 880A Non-Dispersive Infrared Analyzer
GAS
DESICCANT
PART
NUMBER
CO
2
Cardoxide
096218
CO
Mg (CI0
4
)
2
096217
H
2
O
Mg (CI0
4
)
2
096217
SOS
Mg (CI0
4
)
2
096217
CH
4
Mg (CI0
4
)
2
096217
Hexane
Mg (CI0
4
)
2
096217
CO + CO
2
Car Mg (CI0
4
)
2
096217/096218
T
ABLE
6-1. T
YPES OF
D
ESICCANT
6.2 CELL DESICCANT
The reference cell may use a flowing reference. If so, desiccant is required.
A desiccant holder is used on the inlet and outlets to keep moisture from entering the
reference cell (see Figure 6-1). The desiccant should be replaced each time the cell is
opened. To determine the type of desiccant used, refer to Table 6-1. Before inserting
desiccant, purge cell with dry inert gas (i.e., N
2
).
6.3 SOURCE REPLACEMENT
Refer to Figure 6-2. Sources are marked with the resistance value, for example, 11.5 -
11.6 in matched pairs. Install the higher value as the reference source.
Note:
Observe how the parts are disassembled so that the reverse procedure can be
used for reassembly.
1. Loosen the two screws on the front of the case and slide the front panel forward.
2. Remove the two screws holding the source housing to the chopper housing.
3. Remove the two screws holding the source to the source housing. Note how the
source is mounted. There is a front and back side.
4. If replacing the source, insure that its orientation is exactly the same as the old
one. Each source is marked on the back. Install the source with the higher
designation at the reference site.
5. Reverse the procedure outlined above to reinstall the new source assembly,
ensuring teflon spacers are in place and the screws have not been overtightened.
Sources are ceramic and can crack or break under excessive pressure.
6.4 SOURCE BALANCE SHUTTER ADJUSTMENT
When the sources are replaced, follow the Source Balance Procedure in Section 5.6 to
adjust the source balance shutter.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
