Hach ORBISPHERE C1100 User Manual page 27

16. On the sensor cleaning and regeneration center, turn the knob to the Guard position and
press the TIMER switch. Again, watch for the formation of bubbles and repeat the cleaning
process if necessary.
17. On the sensor cleaning and regeneration center, turn the knob to the Cathode position and
press the TIMER switch. Again, watch for the formation of bubbles and repeat the cleaning
process if necessary.
18. When cleaning is complete, unplug the sensor from the cleaning center and re-install the
plastic sensor base for the rest of the procedure. Remove any remaining electrolyte by
rinsing the sensor head with deionized water for 15 seconds, aiming the jet of water directly
onto the sensor head.
Note: For DG33619 regeneration cell, unscrew the regeneration cell from the sensor head.
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19. With the help of a pair of tweezers, remove the old O-ring from the sensor body. Replace
the Oring with a new one from the recharge kit.
Chemical exposure hazard. Obey laboratory safety procedures and wear all of the
personal protective equipment appropriate to the chemicals that are handled. Refer
to the current safety data sheets (MSDS/SDS) for safety protocols.
20. Once the sensor has been successfully cleaned and polished, a final nitric acid treatment
should be applied, as follows:
a. Place the sensor in a vertical position on its base. Place a drop of nitric acid on the
center of the sensor head, covering only the electrode and guard ring.
b. Wait approximately 5 seconds, then rinse thoroughly with deionized water.
c. Do the procedure again two times.
Note: When cleaning is complete, it is very important to ensure your finger does not come into contact with
the cathode (golden surface) as it could leave greasy deposits on the surface.
Maintenance and Troubleshooting
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C A U T I O N
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