Evoqua WALLACE & TIERNAN SFC, Original Instruction Manual

Page: 227 / 288

SFC
Maintenance
7.
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4 Rinse the fine filter with water, replace if necessary.
5 Place the fine filter into the filter unit.
Ensure that the O-ring is fitted correctly (insert as far as
possible).
6 Fit the filter unit. Ensure that it is fitted in the correct position.
7 Tighten both knurled nuts (A).
7.3 Maintaining membrane sensors
For the membrane sensor maintenance procedure, see 4.2.6
“Membrane sensors”.
Please refer to instruction manual „membrane sensor for free
chlorine FC2“ and „membrane sensor for total chlorine TC3“.
7.4 Maintaining Redox electrode
Depending on how dirty the sample water is, the Redox electrode
must be cleaned at certain intervals. Unclean water causes the
measurement to be very slow. At the same time, the Redox
voltage is frequently indicated as too low. The surface of the
platinum disc is usually soiled. This may be to some extent in the
form of an invisible coating. In particular, the ceramic electrode
diaphragm may also be soiled or coated with lime deposits.
To clean the soiled metal disc, the Redox electrode is removed
from the flow-through adapter and cleaned with a paper towel; use
diluted hydrochloric acid (up to 10 %), if necessary. Scouring
cleaner may not be used because it may clog the diaphragm. Then
rinse well with water. Do not touch the platinum electrode after
rinsing in order to keep oil from fingers off them. To remove lime
deposits, immerse the electrodes just past the diaphragms into
hydrochloric acid (10 %); allow several minutes for this to react and
rinse with clear water.
Please note
Do not use any other chemicals than those described here. These
could damage the electrode.