Hanna Instruments wm 8910 User Manual

4 3

4 2

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

tion HI 7061 for 30 minutes, rinse thoroughly in distilled water
and then follow the Cleaning Procedure above.

• 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.

SHORT DISTANCE, INDOOR INSTALLATION

Due to the low current 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

12  

Ω

.

This type of connection is very delicate and requires constant attention
to maintain proper operating conditions.
The conventional electrodes should be used for indoor applications
only, and the cable legth should not exceed 10 m (33').

pH METER

WITH CONVENTIONAL ELECTRODES

MEASUREMENTS CAN BE

TAKEN FROM DISTANCES UP TO

10 METERS (33 FEET)

DRY ENVIRONMENT

LESS THAN 80%

RELATIVE HUMIDITY

MAXIMUM 10 METERS

For refillable electrodes**:
Refill the electrode with fresh electrolyte (HI 7071 for single junction
or  HI 7082 for double junction electrodes). Allow the electrode to
stand upright for 1 hour. Follow the Storage Procedure above.

CLEANING PROCEDURE

Soak in Hanna HI7061  General Cleaning Solu-
tion for approximately ½ hour.

Removal of films, dirt or deposits on the membrane/junction:
Protein

Soak in Hanna HI7073  Protein Cleaning Solu-
tion for 15 minutes.

Soak in Hanna HI 7074 Inorganic Cleaning Solu-
tion for 15 minutes.

Rinse with Hanna HI 7077 Oil and Fat Cleaning
Solution.

IMPORTANT: After performing any of the cleaning procedures rinse
the electrode thoroughly with distilled water, drain and refill the
reference chamber with fresh electrolyte, (not necessary for gel-filled
electrodes) and soak the electrode in HI 70300 Storage Solution for
at least 1 hour before reinstalling it.

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.

- Loss of shielding due to low electrolyte level (in refillable

electrodes only): refill with HI 7071  for single junction or
HI 7082 for double junction electrodes.

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

for at least 1 hour. Check to make sure the installation is such as
to create a well for the electrode bulb to constantly remain moist.

• Drifting: Soak the electrode tip in warm Hanna Solution

HI 7082 for one hour and rinse tip with distilled water (refill
with fresh HI 7071 for single junction electrodes and HI 7082 for
double junction electrodes if necessary).

• 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.

**For industrial applications, gel-filled electrodes are preferable due to lesser maintenance requirements.