55
16.3 Conductivity / TDS Troubleshooting
Symptom
Possible Causes
Remedy
Unit fails to calibrate, even
with new probe.
Calibration settings outside of
allowable limits due to previous
failed calibration.
Check that the k factor is set correctly when
not using a TPS k=10 sensor.
Initialise the unit. See section 12.
Unit attempts Span
calibration instead of Zero
calibration.
Sensor has Zero error.
Thoroughly rinse sensor in distilled water
and allow to completely dry in air before
attempting zero calibration.
DO NOT rub the platinised electrode
surfaces.
If instrument does not calibrate at Zero with
sensor disconnected, then the instrument is
faulty.
Standard calibration fails,
and k factor is greater than
25%
above
the nominal
value.
1.
Sensor is not immersed
correctly.
2.
Sensor may have a build-up
of dirt or oily material on
electrode plates.
3.
Platinum-black coating has
worn off.
4.
Standard solution is
inaccurate.
5.
Sensor is faulty.
6.
Faulty instrument.
Immerse sensor correctly as per diagrams in
section 4.4.
Clean sensor as per the instructions detailed
in section 17.2.1.
Sensor requires replatinization as per
section 17.2.1. Alternatively, return to the
factory for replatinization.
Replace standard solution.
Return sensor to factory for repair or
replacement.
Return to factory for repair.
Standard calibration fails,
and k factor is greater than
25%
below
the nominal
value.
1.
Standard solution is
inaccurate.
2.
Sensor may have a build-up
of conductive material, such
as salt.
3.
Sensor is faulty.
4.
Faulty instrument.
Replace standard solution.
Clean sensor as per the instructions detailed
in section 17.2.1.
Return sensor to factory for repair or
replacement.
Return to factory for repair.
Inaccurate readings, even
when calibration is
successful.
1.
Sensor may have a build-up
of dirt or oily material on
electrode plates.
2.
Platinum-black coating has
worn off.
Clean sensor as per the instructions detailed
in section 17.2.1.
Sensor requires replatinization as per
section 17.2.1. Alternatively, return to the
factory for replatinization.
Readings drift.
Sensor may have a build-up of
dirt or oily material on electrode
plates.
Clean sensor as per the instructions detailed
in section 17.2.1.
Readings are low or near
zero.
1.
Sensor may have a build-up
of dirt or oily material on
electrode plates.
2.
Sensor is not immersed
correctly.
3.
Sensor is faulty.
4.
Faulty instrument.
Clean sensor as per the instructions detailed
in section 17.2.1.
Immerse sensor correctly as per diagrams in
section 4.4.
Return sensor to factory for repair or
replacement.
Return to factory for repair.