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Page 40
19.2 Specific Ion, pH and mV Troubleshooting
Symptom
Possible Causes
Remedy
Unit fails to
calibrate, even with
new probe.
Calibration settings outside of
allowable limits due to
previous failed calibration.
Initialise the unit. See section
17.
1 Point calibration
fails
(Specific Ion offset
causes over-range
reading, or pH
asymmetry is
greater than ±1.00
pH.)
1.
Reference junction blocked.
2.
Reference electrolyte
contaminated.
Clean reference junction, as per
instructions supplied with the
pH or reference sensor.
Flush with distilled water and
replace electrolyte.
2 Point calibration
fails
(Specific Ion slope
is less than 50% or
pH Slope is less
than 85%).
1.
Incorrect primary Ion
Standard or pH Buffer.
2.
Ion sensor surface or pH
glass bulb not clean.
3.
Sensor is aged.
4.
Connector is damp.
5.
Ion Standard or pH Buffers
are inaccurate.
Ensure that you are using the
primary Ion Standard or pH
Buffer for which the
WP-90
has been set (sections 3 & 16).
Clean Ion sensor or pH glass
bulb as per instructions
supplied with the sensor.
Attempt rejuvenation, as per
instructions supplied with the
sensor. If not successful,
replace sensor.
Dry in a warm place.
Replace standards or buffers.
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