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CHAPTER 5

Instrument Operation
This chapter describes the basic operation of the Ultrafine Particle
Monitor - Model 651 and describes how to use the controls,
indicators, and connectors found on the front and back panels.

Operating Precautions

Read the following before applying power to the particle monitor:
Review the operating specifications for the Model 651 described
in Appendix A.
Do not operate the Model 651 at temperatures outside the
range of 10C to 35C. If the particle monitor is operated outside
this range, the displayed concentration may be inaccurate.
WARNING
The Model 651 should not be used with hazardous gases such as
hydrogen or oxygen. Using the particle monitor with hazardous gases
may cause injury to personnel and damage to equipment.

Recommended Operation Procedures

Outdoor Operation Procedures

When sampling outdoor aerosol, follow these recommendations:
Place the Model 651 in a conditioned enclosure or shelter to
ensure that it is operating within temperature and humidity
specifications.
If the Model 651 is placed in an environment with temperatures
lower than the ambient temperature, consider heating the
sample line to reduce condensation.
If you are not using a sampling system, use a cyclone with a cut
size no greater than 3 µm on the particle counter inlet.
Ensure that the pressure differential at the inlet is not greater
than 2.5 kPa (10 inches of H2O). If you are using a cyclone, do
not exceed the inlet pressure drop of 2.5 kPa.