Section 8
8-2
Troubleshooting
Zero and/or Span Adjustments Difficult to Set.
If the zero and/or span adjustments are difficult to set, check to see that the
analyzer is configured correctly (jumper tubes, soda lime/desiccant, etc.).
Also check to make sure that the flow through the analyzer is first entering
the portion of the scrubber tube assembly containing the soda lime, not the
magnesium perchlorate.
Make sure external soda lime/desiccant is fresh. Check for leaks on the
desiccant tube (caps on tight). Check for internal leakage as follows:
Configure the analyzer for absolute mode measurement. Flow CO
2
-free air
through the sample cell, and breath into the cool-air intake filter (just below
the RS-232C port) at the back of the analyzer. The displayed CO
2
should
not rise by more than a few ppm. A sharp rise in the displayed CO
2
coinciding with your breathing indicates a leak. A slow increase of 2 to 3
ppm (depending on the flow rate of air through the sample cell) can be
expected due to diffusion of CO
2
through the Bev-a-line tubing and does not
indicate a leak.
Analyzer Displays CO
2
, H
2
O, and/or AUX instead of values.
This indicates an over range condition of the CO
2
, H
2
O, and auxiliary inputs,
respectively.
Analyzer Displays Zero for CO
2
or H
2
O Values.
•
Check the calibration lists (FCT 01 and 02).
•
Check pressure (FCT 43). If FCT 73 is set to 43 then pressure is
computed from FCTS 71, 72, and 44. Otherwise, it comes from FCT 77.
