Hach-Lange PHC30103 User Manual - Manual (Page 12)

Message or symptom Possible cause Action
Drifting/Inaccurate readings Contaminated glass bulb Clean the probe (refer to Clean the probe on page 9).
CO
2
absorption (for low ionic
strength or high purity sample)
Use the LIS chamber for LIS/high purity samples to
prevent sample contamination.
Clogged reference Rinse the reference junction holes with deionized water
and then gently tap the probe with hand or shake the
probe to remove any air bubbles.
Improper storage conditions/
Dehydrated glass bulb Clean or condition the probe and do recalibration.The
probe may not operate correctly if the probe has been
left dry for a long time. Condition the glass sensor and
reference junctions again:
1. Soak the probe tip in the 4.01, 7.00 and
10.01 buffers each for 5 minutes.
2. Rinse with deionized water. Blot dry with a lint-free
cloth.
3. Calibrate the probe.
Electromagnetic Forces (EMF)
such as voltaic cells,
thermoelectric devices, electrical
generators, resistors and
transformers Do not test in areas where EMF is present. For testing in
process units (spot checking), make sure that the
equipment is grounded.
Colloidal and/or particulates in the
filling solution. Replace the filling solution, calibrate and test again.
Air bubbles around inner
reference electrode Gently tap the probe with hand or shake the probe
downward to remove any air bubbles.
Out of range Measurement value is outside of
range Make sure that the sample is within the range of the
probe.
Out of limits Check standard value is outside of
limits set in the current method Make sure that the standard is within the limits of the
current method.
Create another method that expands the acceptable
limits.
Measurement value is outside of
measurement limits set in the
current method. Make sure that the sample is within the limits of the
current method.
Create a new method with an expanded range.
Temperature out of range Temperature value is outside of
range Make sure that the sample temperature is within the
range of the probe.
Make sure that the temperature sensor is working
correctly.
Measured temperature is outside
the range of the probe Make sure that the standard temperature is within the
range of the probe.
Make sure that the temperature sensor is working
correctly.
Check standard temperature value
is outside of range Make sure that the check standard temperature is within
the range of the probe.
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