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11.3 pH Troubleshooting
Symptom
Possible Causes
Remedy
Unit fails to
calibrate, even
with new sensor.
Calibration settings outside
of allowable limits due to
previous failed calibration.
Initialise the unit. See
section 10.
1 Point calibration
fails (Asymmetry
is greater than +/-
1.00 pH).
1. Reference junction
blocked.
2. Reference electrolyte
contaminated.
Clean reference junction, as
per instructions supplied
with the sensor.
Flush with distilled water
and replace electrolyte.
2 Point calibration
fails (Slope is less
than 85.0%).
1. Incorrect primary buffer.
2. Glass bulb not clean.
3. Sensor is aged.
4. Connector is damp.
5. Buffers are inaccurate.
Ensure that you are using
the buffers which the
Aqua-DP
has been set to
automatically recognise
(See section 8).
Clean 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 buffers.
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