202 • Start Up and Normal Operation
EAGLE 2 Operator’s Manual
CO
2
Scrubber
A carbon dioxide scrubber is mounted to the exterior side of EAGLE 2s that are factory-
shipped with carbon dioxide sensors for the ranges of 0-5 %vol and 0-10,000 ppm.
NOTE:
EAGLE 2s with a range of 0-60 %vol CO
2
do not include a scrubber since the
normal background of CO
2
in air is negligible when compared to the full scale
of these units.
This scrubber is for use when setting the carbon dioxide sensor’s zero reading only. Two
black vinyl caps cover either end of the carbon dioxide scrubber. To prolong the life of the
scrubber, be sure the caps are installed while the scrubber is not in use or while it is being
stored. Replace the scrubber when it turns from white to a violet color.
Figure 41: Carbon Dioxide Scrubber
Start Up and Normal Operation
For instructions to startup and use an EAGLE 2 that includes an infrared CO
2
sensor,
reference “Start Up” on page 27, “Measuring Mode, Normal Operation” on page 33, and
“Measuring Mode, Alarms” on page 38. Follow these instructions keeping the following
special considerations in mind:
•
A background level of CO
2
exists in fresh air. The low range sensors will display a
reading in fresh air. Table 24 below indicates typical gas readings in fresh air.
•
When you perform a demand zero during start up, operation, or calibration of a 0-
10,000 ppm or 0-5 %vol CO
2
instrument, you must use the CO
2
scrubber provided
with the instrument to remove background CO
2
from the air being sampled. See
“Performing a Demand Zero for Carbon Dioxide Sensors” below.
•
Since there is a background of CO
2
in air, do not use the AUTO FRESH AIR ADJ
feature that can be turned on and off in Setup Mode. The factory setting for the feature
is off.
Table 24: Carbon Dioxide Fresh Air Readings
Sensor
Range
Approximate Fresh Air
Reading
0-5 %vol
0.04 %vol
0-10,000 ppm
400 ppm
0-60 %vol
0.0 %vol
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