Analytical Industries GPR-1535 GB Trace PPM Oxygen Transmitter - Manual (Page 23)

Advanced Instruments Inc.
23
Symptom Possible Cause Recommended Action
Erratic O
2
reading
or
No O
2
reading
Test sensor independent from transmitter
Change in sample pressure
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
Liquid covering sensing area
Improper sensor selection
Presence of 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.
Contact factory with result.
Sensors without PCB use mV setting.
Calibrate the transmitter (calibrate at pressure
and temperature of sample)
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
Wipe with alcohol and lint free towel or flow
sample or zero gas for 2-3 hours to flush
Replace GPR/PSR sensor with XLT sensor when
CO
2
or acid gases are present
Consult factory
Replace sensor and install scrubber
Replace sensor, obtain authorized service
Replace sensor
Erratic O
2
reading
or
Negative O
2
reading
or
No O
2
reading
possibly
accompanied by
electrolyte leakage
Pressurizing the sensor by flowing gas to the
sensor with the vent restricted or SHUT OFF
valve which places a vacuum on the sensor in
excess 4” of water column, something which is
strongly discouraged. The
front sensing
membrane is .000625 thick, heat sealed to the
sensor body and subject to tearing when
vacuum is suddenly applied.
A premature adjustment of the ZERO OFFSET
potentiometer is a common problem
Zero the transmitter. If not successful replace the
sensor
Avoid drawing a vacuum on the sensor
From MAIN MENU select DEFAULT ZERO