Analytical Industries GPR-35 Oxygen Analyzer - Manual (Page 29)

Advanced Instruments Inc.
29
Symptom Possible Cause Recommended Action
Erratic O
2
reading
Change in sample pressure
Liquid covering sensing area
Presence of interference gases
Presence of sulfur gases and/or CO
2
Unauthorized maintenance
Dirty electrical contacts in upper section of sensor
housing
Corroded solder joints on sensor PCB from corrosive
sample or electrolyte leakage from sensor
Corroded spring loaded contact in upper section of
sensor housing from liquid in sample or electrolyte
leakage from sensor
Repeat calibration at the temperature and pressure of
sample
Wipe with alcohol and lint free towel or flow sample or zero
gas for 2-3 hours to flush
Consult factory
Replace sensor and install scrubber, contact factory
Replace sensor, obtain authorized service
Clean contacts with alcohol (minimize exposure time of MS
sensor to ambient air to extent possible)
Replace sensor and return sensor to the factory for
warranty determination
Upper section of sensor housing: Clean contacts with
alcohol, flow sample or zero gas for 2-3 hours to flush
sample system and sensor housing
Sensor: Replace if leaking and return it to the factory for
warranty determination
No O
2
reading
Negative O
2
reading
Failure of an electronic component or power surge
that sends a charge to the sensor
Pressurizing the sensor by:
a) Flowing gas to the sensor with the vent restricted
or SHUT OFF valve closed and suddenly removing
the restriction draws a vacuum and can damage the
sensor and/or cause electrolyte leakage
b) Drawing a vacuum on the sensor by partially
opening the FLOW valve upstream of the sensor
when using a pump downstream to draw sample
from a process at atmospheric pressure or a slight
vacuum can damage the sensor and cause it to leak
electrolyte
Service the analyzer, check the power source and THEN
replace the sensor
Introduce span gas to determine if the sensor responds.
If successful calibrate the analyzer and resume sampling
If not successful, inspect for electrolyte leakage, check and
clean the contacts in the upper section of the sensor
housing, flow a little warm water followed by air or clean
sample through the analyzer for 2-3 hours to push the
electrolyte through the sample system and THEN replace
the sensor