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18.3 Ratio Troubleshooting
Any possible causes related to the sensor in this section could be due to the sensor plugged into
Cond/TDS
or
Ratio
socket or both. If in doubt, always check both sensors.
Symptom
Possible Causes
Remedy
Unit will not proceed to
Ratio mode, even with
matching k factor sensors
connected to
Cond / TDS
and
Ratio
sockets
1. Sensor connectors are not
correctly coded.
Ensure that you are using genuine TPS
Conductivity sensors. If not, contact TPS
for details on k factor coding.
Cell / Solution match check
fails, even with new probe.
1. Calibration settings outside
of allowable limits due to
previous failed calibration.
Initialise the unit. See section 16.
Calibration fails. Span
difference between the two
sensors is >200% or < 50%.
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 at least to the vent hole in
the side of the sensor.
Clean sensor, as per the instructions
detailed in section 19.3.
Sensor requires replatinisation, as per
section 19.4. Alternatively, return to the
factory for replatinisation.
Replace standard solution.
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.
3. Platinum-black coating has
worn off.
Clean sensor, as per the instructions
detailed in section 19.3.
Sensor requires replatinisation, as per
section 19.4. Alternatively, return to the
factory for replatinisation.
Readings drift.
1. Sensor may have a build-up
of dirt or oily material on
electrode plates.
Clean sensor, as per the instructions
detailed in section 19.3.
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 19.3.
Immerse sensor at least to the vent hole in
the side of the sensor.
Return sensor to factory for repair or
replacement.
Return to factory for repair.