Instruction Manual

748332-F April 2003

Model NGA2000 NDIR

4-12 CLEANING CELLS

When zero gas is introduced in the SAMPLE IN inlet and the Detector signal is greater 1.2V, the cells and windows require cleaning. To do this, follow this procedure:

See Figure 4-8 on page 4-9 to identify which detail drawing best matches the configuration in question.

Fold out the PCB panel.

Disassemble the optical bench according to Figure 4-5 on page 4-5 and the cells according to Figure 4-8 on page 4-9.

Rinse the cell with acetone. If this does not remove all foreign matter, use a soft brush. Do not use any metallic object inside the cell because it will scratch the gold plating. Loss of gold plating may require cell replacement.

After all matter has been removed, rinse the cell with distilled water and allow to air dry. Do not use towels.

Inspect the cell inside by holding it up to a bright light. If particles are seen, repeat Steps 5 and 6 as often as necessary.

After cleaning cell, examine O-rings at the source, detector and end caps. If damaged, replace with new O-rings.

Remove any contaminants from windows with a lint-free cloth soaked in acetone. Do not use alcohol or other solvents. Allow to air dry.

Reverse disassemble instructions to reassemble the unit.

Perform a leak check.

Replace desiccant if required. (See Section 4-13 on page 4-10.)

After cleaning cells, the Analyzer Module must be optically aligned if the diagnostic values for oscillator tune and detector signals are not within ±5% of the factory settings. If they are not within that range, follow Steps 7 through 10 of Section 4-11 on page 4-6.

4-8 Maintenance and Troubleshooting

Rosemount Analytical Inc. A Division of Emerson Process Management