Maintenance; Replacement Of The Electrode; Storing And Cleaning Of The Electrode - Burkert 8205 Notice D'utilisation

5 MAINTENANCE

5.1 Replacement of the pH electrode (compact controller only)
pH-electrodes have a limited service life, depending upon many
parameters, such as the chemical composition of the handled fluid,
temperature, pressure, etc.
The manufacturer warranty for the 8205 does not cover the pH electrode.
The electrode must be replaced if it shows visible damage (broken glass, fractures, etc.)
or if the message "ERROR" is displayed at the end of calibration.
For replacement, proceed as follows:
1. Disconnect supply voltage and make sure that there is no pressure on
pipe or tank.
2. Remove the controller from the pipe or submersion assembly.
3. Lift the transparent lid after having unfastened the screw. Unscrew the cover and open
it slightly.
4. Pull out pH and temperature cables from the electronic board.
5. Pull sensor assembly out of the enclosure.
6. Screw electrode out of assembly with SW17 wrench.
7. Screw new electrode into assembly and tighten with SW17 wrench. Reassemble in
reverse order.

5.2 Storing and Cleaning of the Electrode

When not in operation, the electrode should be stored in a 3 molar potassium chloride
solution (223,6 g/l), providing a regenerative effect. Is there no such solution available,
normal tap water will also do for short measuring interruptions of max. 2 - 3 days. The
electrode must not be stored in distilled or deionisized water, which may be used for
rinsing purposes only!
Experience has shown, that the majority of failures in pH electrode measurements and
long response times originate from contaminated electrodes or diaphragms. Since the
contamination is subject to the application, there is no general detergent available yet. The
following detergents, however, can be recommended for most application cases:
-Greasy or oily deposits must be removed with a tenside-containing agent.
-Chalky deposits and metal hydroxide layers require diluted hydrochloric acid (10%).
-Sulphide-containing deposits (purification systems) are removed with a detergent mixture
of diluted hydrochloric acid (10%) and saturated pepsin.
-For very slow pH-electrodes dip the electrode for 1 minute into a 2% HF and 5% HCL
solution and rinse thoroughly.
PH CONTROLLER 8205
E-36-