Hach-Lange ISENa38103 - Manual (Page 13)

Message or symptom Possible cause Action
Slow stabilization time
Tape not removed from the filling hole Remove the tape.
Contaminated glass sensor Clean the probe (refer to Clean the probe
on page 11).
Contaminated filling solution Drain and replace the filling solution with fresh
solution.
Filling-hole cap is closed Open the filling-hole cap while in use.
Low sample temperature or
temperature difference between
samples Check the sample temperature. The lower the
temperature or the greater the difference of
temperatures between samples, the longer the
response time.
Air bubbles around inner reference
electrode Gently tap the probe with hand or shake the
probe downward to remove any air bubbles.
Slope out of range (refer to
Check probe response
on page 14)
pH is too low Make sure the pH is greater than 9 after each
ISA addition.
Ionic strength adjustor (ISA) not used Add ISA to each sample and standard.
Insufficient conditioning Condition for at least 8 hours in storage solution.
Damaged probe Contact a Technical Support Representative.
Incorrect standards Calibrate using freshly prepared standards.
Contaminated glass sensor Clean the probe and recalibrate.
Air bubbles around inner reference
electrode Gently tap the probe with hand or shake the
probe downward to remove any air bubbles.
Drifting/inaccurate readings
Contaminated glass bulb Clean the probe (refer to Clean the probe
on page 11).
Clogged reference Rinse the reference junction with ISA rinse
solution thoroughly and shake the probe
downward to remove any air bubbles.
Improper storage
conditions/dehydrated glass bulb Clean or condition the probe and attempt another
calibration. The probe may not function correctly
if the probe has been left dry for extended
periods of time. To re-condition the glass sensor
and reference junctions, allow the probe to soak
in storage solution (that contains Sodium ISA) for
at least 8 hours before use.
Stabilization criteria not optimized for
the application Adjust the stabilization criteria in the
Measurement Options menu.
Magnetic stirrers may generate
sufficient heat to change solution
temperature. Put a piece of insulating material between the
stirrer and beaker.
Filling-hole cap is closed Open the filling-hole cap while in use.
Damaged probe Contact a Technical Support Representative.
Electromagnetic Forces (EMF) such as
voltaic cells, thermoelectric devices,
electrical generators, resistors and
transformers Do not use in areas where EMF is present.
Colloidal and/or particulates in the
filling solution Replace the filling solution, calibrate and retest.
Air bubbles around inner reference
electrode Gently tap the probe with hand or shake the
probe downward to remove any air bubbles.
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