Troubleshooting
Follow a systematic procedure to isolate the problem. The measuring system can be divided into four components for ease in troubleshooting: meter, electrode, sample/application
and technique.
Meter
The meter is the easiest component to eliminate as a possible cause of error. Thermo Scientific Orion meters include
an instrument checkout procedure and shorting cap for convenience in troubleshooting. Consult the pH meter user guide for directions.
Electrode
1.Thoroughly rinse the electrode with distilled water.
2.Place electrode in the Orion ORP standard and wait until the reading stabilizes.
3.The mV potential should be 220 mV ± 60 mV. If the mV reading is out of range, repeat the measurement with fresh ORP standard. If the electrode fails this procedure, clean the electrode thoroughly as directed in the Electrode Maintenance section. If the electrode response is slow or drifting and the electrode is refillable, drain and refill the electrode with fresh filling solution. Replace the electrode if cleaning and maintenance fail to rejuvenate it.
Sample/Application
The electrode and meter may operate with standards, but not with the sample. In this case, check the sample composition for interferences, incompatibilities or temperature effects.
Technique
If trouble persists, review operating procedures. Review calibration and measurement sections to be sure proper technique has been followed.
18 | Redox/ORP Electrode User Guide |