Analytical Industries GPR-1535 GB Trace PPM Oxygen Transmitter - Manual (Page 22)

Advanced Instruments Inc.
22
8 Troubleshooting
Symptom Possible Cause Recommended Action
Slow recovery
At installation, defective sensor
Air leak in sample system connection(s)
Abnormality in zero gas
Damaged in service - prolonged exposure to
air, electrolyte leak
Sensor nearing end of life
Replace sensor if recovery unacceptable or O
2
reading fails to reach 10% of lowest range
Leak test the entire sample system:
Vary the flow rate, if the O
2
reading changes
inversely with the change in flow rate indicates
an air leak - correct source of leak
Qualify zero gas (using portable transmitter)
Replace sensor
Replace sensor
High O
2
reading
after installing or
replacing sensor
Transmitter calibrated before sensor stabilized
caused by:
1) Prolonged exposure to ambient air, worse
if sensor was unshorted
2) Air leak in sample system connection(s)
3) Abnormality in zero gas
Allow O
2
reading to stabilize before making the
span/calibration adjustment
Continue purge with zero gas
Leak test the entire sample system (above)
Qualify zero gas (using portable transmitter)
High O
2
reading
Sampling
Flow rate exceeds limits
Pressurized sensor
Improper sensor selection
Abnormality in gas
Correct pressure and flow rate
Remove restriction on vent line or open SHUT
OFF valve completely
Replace GPR/PSR sensor with XLT sensor when
CO
2
or acid gases are present
Qualify the gas (use a portable transmitter)
Response time slow Air leak, dead legs, distance of sample line,
low flow rate, volume of optional filters and
scrubbers
Leak test (above), reduce dead volume or
increase flow rate
O
2
reading doesn’t
agree to expected O
2
values
Pressure and temperature of the sample is
different than span gas
Abnormality in gas
Calibrate the transmitter (calibrate at pressure
and temperature of sample)
Qualify the gas (use a portable transmitter)