Hanna Instruments HI 9912 User Manual

Page 21

For more specific cleaning procedures, refer to the electrode’s instruc-
tion manual.
IMPORTANT: After performing any of the cleaning procedures rinse
the electrode thoroughly with distilled water and recalibrate the
controller.

TROUBLESHOOTING

Evaluate your electrode performance based on the following.
• Noise (Readings fluctuate up and down) could be due to -

clogged/dirty junction: Refer to the Cleaning Procedure above.

• Dry Membrane/Junction: Soak in Storage Solution HI 70300

overnight. Check to make sure the installation is such as to create
a well for the electrode bulb to constantly remain moist.

• Low Slope: Refer to the cleaning procedure above.
• No Slope: - Check the electrode for cracks in glass stem or bulb

(replace the electrode if cracks are found).

- Make sure cable and connections are not dam-

aged nor lying in a pool of water or solution.

• Slow Response/Excessive Drift: Soak the tip in Hanna Solu-

tion HI 7061 for 30 minutes, rinse thoroughly with distilled
water and then recalibrate the meter.

• For ORP Electrodes: Polish the metal tip with a lightly abrasive

paper (paying attention not to scratch the surface) and wash
thoroughly with water.

Note: With industrial applications, it is always recommended to keep

at least one spare electrode handy. When anomalies are not
resolved with a simple maintenance, change the electrode
(and recalibrate the controller) to see if the problem is
alleviated.

SUGGESTED INSTALLATIONS

for pH/ORP ELECTRODES

The electrodes should be installed in such a away that they always lie
in the solution, whether in a well, tank or on the discharge pipe.

SHORT DISTANCE, INDOOR INSTALLATION

Due to the low currents involved, a very high grade of insulation is
required. A dry environment is needed in order to obtain a level of
insulation not lower than 10

Ω