OHAUS ST300 - Maintenance and Troubleshooting; Error Messages and Solutions; Meter Care and Cleaning; Electrode Care and Troubleshooting

EN-14 STARTER 300 Portable pH Meter
5 MAINTENANCE
5.1 Error message
Error 0
Memory access error
Reset to factory settings
Error 1
Self-diagnosis failed
Repeat the self-diagnosis procedure and make
sure that you finish pressing all five keys within
two minutes.
Error 2
Measured values out of range
Check if the electrode is properly connected and
placed in the sample solution.
Error 3
Measured buffer temperature
out of range (<5 or >40 °C)
Keep the pH buffer temperature within the range
for calibration
Error 4
Offset out of range
offset > 60mV or < - 60 mV
Make sure the pH buffer is correct and fresh;
Clean or replace the pH electrode.
Error 5
Slope out of range
Make sure the buffer is correct and fresh; Clean
or replace the pH electrode.
Error 6
Meter cannot recognize the
buffer
Make sure the buffer is correct and fresh; check if
the buffer has not been used more than once.
Error 9
The current data set has
already been stored once
An endpoint reading can only be stored once.
Perform a new measurement to store.
For further technical support please contact Ohaus. (US please contact 1-800-672-7722)
5.2 Meter maintenance
Never unscrew the two halves of the housing!
The STARTER 300 series instruments do not require any maintenance other than replacement of
depleted batteries. To clean, use a damp cloth.
The housing is made of acrylonitrile butadiene styrene (ABS). This material is susceptible to
damage by some organic solvents, such as toluene, xylene and methyl ethyl ketone (MEK). Any
spillage should be immediately wiped off.
5.3 Electrode maintenance
Make sure the electrode is filled with electrolyte solution. Always store the electrode according to
the electrode instruction manuals and do not allow it to dry out.
If the electrode response becomes sluggish or the slope is not acceptable, try the following:
o Soak the electrode in 0.1M HCl for at least 8 hours.
o For fat or oil contaminant, degrease the membrane with cotton wool soaked in either
acetone or a soap solution.
After electrode treatment, a new calibration should be performed. If the electrode slope is still not
acceptable, the electrode might need to be replaced.