
Page 40
19.2 pH and mV/ORP 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
17, Initialising the WP-80M.
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
WP-
80M
has been set to
automatically recognise (see
section 16).
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.
Continued next page...