Advanced Instruments Inc.
Erratic O
2
reading or No
O
2
reading
Test sensor signal output independent
from analyzer
Abrupt changes in sample pressure
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
Liquid covering sensing area
Improper sensor selection
Presence of other interference gases
Presence of sulfur gases
Unauthorized maintenance
Sensor nearing end of life
Remove sensor from housing. Using a volt-
meter set to uA output; apply the (+) lead
to the outer ring of the sensor PCB and the
(-) lead to the center circle to obtain the
sensor’s output in air (expected value 400-
900 uA). If no current signal, replace
sensor, otherwise contact factory.
Regulate sample gas pressure and flow.
Clean contacts with alcohol (minimize
exposure time of sensor to ambient air to
extent possible)
Replace sensor and return damaged sensor
to the factory for warranty determination
Clean spring loaded contacts in upper
section of sensor housing with a damped
cloth. If electrolyte leakage from sensor is
evident, replace sensor and return leaking
sensor to the factory for warranty
determination
Wipe sensor and sensor housing and sensor
with a damped towel.
Replace GPR series sensor with XLT sensor
when CO
2
or other acid gases are present,
consult factory
Replace sensor and install H2S scrubber
Replace sensor, obtain authorized service
Replace sensor
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