Troubleshooting, Clean the probe as needed. refer to – Hach-Lange SENSION+ pH31 User Manual
Page 16
Troubleshooting
Refer to the following table for common problem messages or
symptoms, possible causes and corrective actions.
Table 2 Calibration warnings and errors
Error/Warning
Solution
Asymmetry >
58 mV
Slope out of range (accepted values ± 58 mV).
Calibrate again.
Connect a new probe.
Buffer or electrode
in poor conditions.
Calibrate again.
Examine the probe: Clean the probe (refer to
on page 13 for more information); make sure that
there are no air bubbles in the membrane. Shake the probe
like a thermometer; Connect a different probe to verify if
problem is with probe or meter.
Examine the buffer solution: Make sure that the buffer used
matches the buffer specified in configuration; make sure of
the temperature specification in configuration; use new
buffer solution.
Sens. (a) < 70%
BUFFER NOT
RECOGNIZED
UNSTABLE
READING
Time t> 100 s
Calibrate again.
Examine the probe: Clean the probe (refer to
on page 13 for more information); make sure that
there are no air bubbles in the membrane. Shake the probe
like a thermometer; connect a different probe to verify if
problem is with probe or meter.
Make sure that the membrane and the diaphragm are
properly immersed in the sample.
Table 2 Calibration warnings and errors (continued)
Error/Warning
Solution
Electrode in poor
conditions.
Examine the probe: Clean the probe (refer to
on page 13 for more information); make sure that
there are no air bubbles in the membrane. Shake the probe
like a thermometer; connect a different probe to verify if
problem is with probe or meter.
Check the
electrode
SAME BUFFERS
Calibrate again.
Examine the probe: Clean the probe (refer to
on page 13 for more information); make sure that
there are no air bubbles in the membrane. Shake the probe
like a thermometer; connect a different probe to verify if
problem is with probe or meter.
Examine the buffer solution: Use new buffer solution.
Table 3 Measurement warnings and errors
Error/Warning
Solution
pH 12.78 19°C
Calibrate again
pH out of range
Examine the probe: Clean the probe (refer to
on page 13 for more information); make sure that
there are no air bubbles in the membrane. Shake the
probe like a thermometer; connect a different probe to
verify if problem is with probe or meter.
Temp out of range
°C
Examine the temperature sensor.
Connect a different probe to verify if problem is with probe
or meter.
Time > 60 s
Make sure that the membrane and the diaphragm are
properly immersed in the sample.
Examine the temperature.
Examine the probe: Clean the probe (refer to
on page 13 for more information); make sure that
there are no air bubbles in the membrane. Shake the
probe like a thermometer; connect a different probe to
verify if problem is with probe or meter.
Time > 150 s
Time > 300 s
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