19
c.
The chromatograph run time and the carrier air pressure have a give and take
relationship. If the run time is increased, then decrease the carrier air pressure. If
the run time is decreased, then increase the carrier air pressure.
Chromatograph Peaks Appear with no Baseline
1.
Re-zero the GC filament while the chromatograph is stopped and complete another
calibration run.
2.
Check the scales of the chromatogram. Some adjustment may be needed.
Chromatograph Appears as just an Erratic Scribble
1.
Check the exhaust lines and be sure they are attached and running to an outside
location to exhaust.
a.
Be sure the carrier air intake is not sucking in any exhaust from the exhaust
lines.
2.
Check for interference from an electromagnetic field.
a.
Check for any fuzz buster, HAM radio antenna, or satellite phone in operation
close by.
b.
Cell phones in use next to the MLogger can sometimes affect the filament
signals. Use the phone a distance away from the MLogger.
MControl Chromatograph Readings aren’t Displaying Heavy Gases
1.
Increase the run time to twelve minutes and run another chromatograph. Do not
increase the run time to more than fifteen minutes.
2.
Increase the carrier air pressure (do not exceed 12 PSI) and then increase the run
time.
Chromatograph Baseline Wanders
1.
Check the exhaust lines at the back of the MLogger. The carrier air may have sucked
in exhaust gas from the detector. Recycled gas shows up as strange curves and peaks
in the chromatograph.
a.
The detector exhaust, chromatograph exhaust, and the main exhaust must all
have lines connected to them. Run these lines to the outside of the trailer.
