Advanced Instruments Inc.
Erratic O
2
reading or
Negative O
2
reading or
No O
2
reading
possibly accompanied
by electrolyte leakage
Fails Span Calibration
Fails Zero Calibration
Analyzer does not
power up
Pressurizing the sensor by flowing
gas to the sensor with:
the vent restricted or
SHUT OFF valve closed and the
suddenly removing the
restriction draws a vacuum on the
sensor or
partially opening the valves
upstream of the analyzer when
using a pump downstream of the
analyzer to draw sample from a
process at atmospheric pressure or
a slight vacuum
A pressurized sensor may not leak
but still can produce negative
readings.
Placing a vacuum on the sensor in
excess 40” of water column is
strongly discouraged. The front
sensing membrane is only 5/8 mil
thick, heat sealed to the sensor
body and is subject to tearing when
vacuum is suddenly applied.
A premature ZERO OFFSET of
analyzer is a common cause
Sensor output beyond
recommended range
Zero offset beyond the permitted
range
Sensor output of spec, span gas
incorrect
Zero offset beyond acceptable limit,
contaminated zero gas
Low battery
Zero the analyzer. If not successful replace
the sensor
Avoid drawing a vacuum on the sensor
From MAIN MENU select DEFAULT ZERO and
perform a zero calibration again. If
unsuccessful, replace sensor
Replace sensor
Perform DEFAULT ZERO, wait until the offset
is less than 50% of the lowest range,
perform zero calibration again
Check integrity of span gas, if OK, replace
sensor
Check integrity of zero gas, wait until zero
offset falls below the acceptable limit
Charge battery, if unsuccessful, replace
battery
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