Hanna Instruments HI 904 - Manual (Page 105)

8-3
MAINTENANCE, PERIPHERALS
8 MAINTENANCE, PERIPHERALS
8.1 Generator Electrode Maintenance
Caution: Never heat generator electrodes over 50ºC when drying! This could
cause permanent damage to the connector!
Generator electrodes should be cleaned every 1-2 weeks, more frequently if working with
“dirty” or “oily” samples.
1. Remove the desiccant cartridge from the top of the generator and disconnect the
cable. For generators with diaphragm, use the waste tube to remove the catholyte
from the inner compartment.
2. Remove the generator from the titration vessel.
3. Rinse the inner and outer surfaces with dry methanol. Do NOT let any liquid/
solvent get near the connector of the electrode!
4. For generators with diaphragm, place the generator in an empty titration vessel
and fill the inner compartment with approximately 15-20 mL of dry methanol.
Allow the methanol to (slowly) diffuse through the diaphragm to clear it of possible
contaminants. For a more thorough cleaning, allow 1 or 2 more aliquots of dry
methanol to diffuse through the diaphragm.
5. Wipe joint grease off of the ground-glass joints with a clean, dry cloth or tissue.
6. Allow the generator to dry. Place in a drying oven (max 50ºC) for 1 hour, or until
no liquid/condensation is visible. If no oven is available, it is better to use the
generator immediately in order to avoid adsorption of moisture on residual methanol
- especially when using generators with a diaphragm.
7. If visible contamination remains, use an appropriate solvent that will dissolve the
contaminant. Soap and water may be used if needed, then rinse and dry.
8.2 Detector Electrode Maintenance
Proper detector maintenance is crucial for reliable measurements and extending the
life of the detector. The frequency of maintenance will depend largely on the type of
samples that are analyzed. Maintenance may be required if any of the following are
observed:
• Slow or no electrode response
• Noisy mV readings
• Debris on or between electrode pins
• Coating on electrode pins