EGM-5 Operation Manual V. 1.04 24 support@ppsystems.com
Absorber Column and CO
2
Scrubber
The absorber column contains a CO
2
scrubbing desiccant commonly referred to as “soda lime”. When air
passes through this column, it removes all of the CO
2
from the air stream. The “Auto-Zero” function built
into the EGM-5 periodically switches the flow of gas from the analyzer through this column to check the
analyzer zero. This routine ensures long term stability and accuracy of the CO
2
analyzer. It automatically
corrects for such things as sample cell contamination, source aging, detector sensitivity and changes in
electronics. The default Auto-Zero interval is 20 minutes, but this can be changed if required. See Zero
Settings on page 34.
Important Note
It is critical that the soda lime is fresh to ensure that the EGM-5 receives a good zero for long term
calibration and stability of the CO
2
signal. At present, both self-indicating and non-indicating soda lime
can be used with the EGM-5. If using a self-indicating desiccant you can visually determine when the
desiccant is exhausted by change in color. When the desiccant is more than 2/3 exhausted you should
replace it. In addition, the EGM-5 monitors the CO
2
scrubber condition in the upper right hand corner of
the display based on use (see below). This is extremely helpful when using a non-indicating CO
2
scrubber. We recommend changing out the desiccant daily or at minimum when this value gets to 20%.
See Reset Abs Settings on page 38 for information on resetting the CO
2
scrubber after refreshing the
desiccant.
Soda Lime (CO
2
Scrubber)
The EGM-5 is virtually maintenance free. However, the condition of the soda lime should be carefully
inspected before each use to ensure stability and accuracy of CO
2
measurements. Generally speaking,
the soda lime should last for several weeks during regular use. However, given the importance of stability
and accuracy of the CO
2
signal you should consider changing out this desiccant more frequently as
described above (daily).
! CAUTION !
WASH YOUR HANDS AFTER HANDLING SODA LIME
To Next Page
Loading...
Need help?
General
