Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2
8-2
8.2. Replacing the Sample Particulate Filter
The particulate filter should be inspected often for signs of plugging or contamination. It is also
common for dirt particles to absorb NO2, thus causing the reading to be low. A discoloration of
the filter membrane indicates that the filter is dirty and should be changed.
To change the filter:
1. Locate the sample filter on the outside rear panel.
2. Unscrew the hold-down ring, remove the Teflon o-ring and then the filter disc. See
Figure 8-1 for an exploded view of the filter assembly.
3. Replace the filter, being careful that the element is fully seated in the bottom of the holder.
Replace the Teflon o-ring, then screw on the hold-down ring and hand tighten.