Troubleshooting, Clean the probe as needed. refer to – Hach-Lange SENSION+ MM374 User Manual
Page 17
Troubleshooting
Refer to the following table for common problem messages or
symptoms, possible causes and corrective actions.
Table 1 Calibration warnings and errors
Error/Warning
Solution
Calibration out of
range
Measured value out of range.
Calibrate again. Connect a new probe.
Unknown buffer
Calibrate again.
Examine the probe: Clean the probe (refer to
on page 15 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
find if the problem is with the probe or the 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
a new buffer solution.
Same buffer /
standard. Re-
calibrate
Unstable
measurement
Time > 100 s (pH,
EC and DO
calibrations)
Time > 240 s (ISE
calibrations)
Calibrate again.
Examine the probe: Clean the probe (refer to
on page 15 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
find if the problem is with the probe or the meter.
Make sure that the membrane and the diaphragm are
properly immersed in the sample.
Temperature
difference > 3.0 ºC
Adjust the calibration solutions to the same temperature.
Examine the temperature sensor.
Temperature out of
range
Examine the temperature sensor.
Connect a new probe.
Table 1 Calibration warnings and errors (continued)
Error/Warning
Solution
Outside allowable
range
Offset or Slope outside the range.
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
a new buffer solution.
Examine the probe: Clean the probe (refer to
on page 15 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
find if the problem is with the probe or the meter.
Signal too low / high
(DO calibrations)
DO probe error.
Examine the probe. Connect a different probe to make
sure that if problem is with probe or meter.
Use a new standard solution.
Cell constant over
limits (EC
calibrations)
Insert the probe into the appropriate standard and re-
read.
Examine the probe: Clean the probe (refer to
on page 15 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
find if the problem is with the probe or the meter.
Cell constant
deviation error (EC
calibrations)
Not calibrated
There are no calibration data stored in the instrument.
Perform calibration.
English 17