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

5 MAINTENANCE

5.1 Replacement of the pH electrode

pH-electrodes are consumables and have thus a limited service life, de-
pending upon many parameters, such as the chemical composition of the
handled fluid, temperature, pressure, etc.
The manufacturer's warranty does not cover the pH electrodes.
The electrode must be replaced if it shows visible damage (broken glass, fractures, etc.) or
if the messages "WARNING" or "ERROR" are displayed at the end of calibration.
For replacement of the electrode, proceed as follows:
1. Disconnect supply voltage and make sure that there is no pressure on
pipe or tank.
2. Remove the transmitter from the pipe or submersion assembly.
3. Unscrew the cover and open it slightly.
4. Pull out pH and temperature cable connectors 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 so-
lution (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 contami-
nation 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.
Observe safety regulations, when handling acid-containing solutions.
Always rinse electrode with deionisized water and leave for approx. 10
minutes in a 3 molar potassium chloride solution or in tap water.
PH TRANSMITTER 8205
E-34-