Evoqua WALLACE & TIERNAN SFC, Original Instruction Manual

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WT.050.590.000.DE.IM.0719
Maintenance
SFC
7.
7.5 Maintaining pH electrode
Clean and calibrate if there are fluctuations in the measured
values. A routine schedule cannot be given here because the
cleaning schedule depends heavily on the general condition of the
sample water. In general, calibrate approx. every 4 weeks.
Remove dirt on the glass membrane and diaphragm to prevent
measuring errors.
In particular, the ceramic electrode diaphragm may also be soiled
or coated with lime deposits.
Remove contaminants deposited on the surface of the membrane
glass; use diluted hydrochloric acid (up to 10 %), if necessary.
The electrodes should not be cleaned in a dry state because this
is more likely to smear the layer of dirt over the surface rather than
removing it. Under no circumstances may the membrane be
treated with abrasive cleaning agents.
The electrode must be rinsed subsequently with nothing other than
water.
Remove lime deposits on the glass membrane and the diaphragm
by immersing the electrode into hydrochloric acid (up to 10 %).
Rinse thoroughly with water or distilled water here as well; pH
electrodes age. This is often the cause for a slow display of the pH
value or a drop in the span. pH electrodes typically last 1 to 2
years. However, routine maintenance of the electrodes
recommended.
7.6 Maintaining fluoride electrode
Routinely check the electrolyte level in the electrode (at least once
per week). The fill level should always be just under the filling hole,
approx. 25 mm above the sample water. Replenish the electrolyte,
if necessary.
Routinely calibrate the measuring system to guarantee safe
operation and accuracy.
The electrode shaft can be cleaned using a moist cloth.
Do not touch the glass surfaces with the cloth.