Analytical Industries GPR-7500 AIS Trace PPM Hydrogen Sulfide Analyzer - Manual (Page 32)

Advanced Instruments, Inc.
32
Symptom Possible Cause Recommended Action
Response time slow Air leak, dead legs, distance
of sample line, low flow rate,
high volume of optional filters
and scrubbers Leak test entire sample system, reduce
dead volume or increase flow rate
H
2
S read ing doesn’t
agree to expected
values
Pressure and temperature of
the sample is different than
span gas
Error in calibration
Abnormality in gas
Calibrate the transmitter (calibrate at
pressure and temperature similar to that of
sample)
Repeat calibration
Qualify the integrity of the sample gas (use
a portable analyzer as a secondary check)
Erratic H
2
Sreading
or
No H
2
S reading
Sudden Changes in sample
pressure
Loose sensor cable and or
sensor PCB
Incorrect polarity of ribbon
cable
Corroded sensor PCB
Liquid covering sensing area
Sensor nearing end of life
Calibrate the transmitter (calibrate at
pressure and temperature similar to that of
sample)
Maintain sample pressure to within
recommended range
Secure ribbon cable firmly by fully inserting
the ribbon cable into its mating socket on
the sensor PCB
Ensure that sensor PCB is firmly secured
on sensor
Ensure that the conductors of ribbon cable
align with COND on sensor PCB
Replace sensor PCB
Replace sensor
.
Replace sensor
Cannot span
calibrate
Cannot zero
calibrate
Incorrect span gas
Span gas pressure too high
Span flow rate too high
Incorrect sensor
Sensor nearing end of life
Zero offset outside of
recommended range
High sample/zero gas flow
causing back pressure on
sensor
Defective sensor
Check span gas with a secondary analyzer
Set span gas pressure within
recommended range
Set flow rate within recommended range
Replace sensor
Allow enough time for sensor to settle with
zero gas
Set sample/zero gas flow within
recommended range
Replace sensor