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18.2 pH and mV/ORP Troubleshooting
Symptom
Possible Causes
Remedy
Unit fails to
calibrate, even
with new probe.
Calibration settings outside
of allowable limits due to
previous failed calibration.
Initialize the unit. See section
16, Initialising the WP-80D
.
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 electrode.
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. Electrode is aged.
4. Connector is damp.
5. Buffers are inaccurate.
Ensure that you are using
the buffers which the
WP-
80D
has been set to
automatically recognise (see
section 15).
Clean glass bulb as per
instructions supplied with the
electrode.
Attempt rejuvenation, as per
instructions supplied with the
electrode. If not successful,
replace electrode.
Dry in a warm place.
Replace buffers.
Unstable
readings.
1. Electrolyte chamber
needs to be refilled.
2. Reference junction
blocked.
3. Glass bulb not clean.
4. Bubble in glass bulb.
5. Faulty connection to
meter.
6. Reference junction not
immersed.
7. KCl crystals around
reference junction, inside
the electrolyte chamber.
Refill with saturated KCl
filling solution.
Clean reference junction, as
per instructions supplied with
the electrode.
Clean glass bulb as per
instructions supplied with the
electrode.
Flick the electrode to remove
bubble.
Check connectors. Replace
if necessary.
Ensure that the bulb AND
the reference junction are
fully immersed.
Rinse electrolyte chamber
with warm distilled water until
dissolved. Replace
electrolyte.