Hach ISEF121 Series, Руководство пользователя

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Section 9 Troubleshooting
Refer to Table 2 for general troubleshooting information. To check the probe performance, refer to
Slope check on page 12. To check the accuracy of sample measurements, refer to Standard
additions check on page 12.
Table 2 Troubleshooting information
Problem Possible cause Solution
Decreased probe performance
causes slow stabilization and
prevents accurate calibrations or
measurements.
The probe has contamination
on the sensing element. Clean and condition the probe.
Refer to
Clean the probe
on page 10.
The reference junction is
clogged. Fully rinse the reference junction
with deionized water. Shake the
probe down to remove air
bubbles.
The probe is not conditioned
to the sample sufficiently. Condition the probe. Refer to
Preparation for use on page 5.
Sample properties cause slow
stabilization or inaccurate
measurements.
The sample pH with ISA is
incorrect. Make sure that the sample pH
after the ISA is added is
between 5.0 and 5.5. Make sure
to add one ISA pillow to each
25 mL of sample.
The sample temperature is
low, or there is a large
temperature difference
between samples. Increase the sample
temperature or adjust the
temperature of different samples
to be the same (within 2 °C
(3.6 °F)).
Procedure problem causes slow
stabilization and prevents
accurate calibrations or
measurements.
Air bubbles are around or
below the probe tip. Carefully tap or shake the probe
to remove air bubbles.
The ISA was not added. Add one ISA powder pillow to
each 25 mL of sample and
standard solution.
The stir speed is too slow or
too fast. Try a different stir speed.
Magnetic stirrers can
become warm and increase
the solution temperature. Put a piece of insulating material
between the stirrer and beaker.
An incorrect standard
solution was used or the
standard solution has
contamination. Use the specified standard
solution of good quality.
Too much time passed after
the ISA was added. Measure the sample or standard
solutions immediately after the
ISA is added.
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