Evoqua WALLACE & TIERNAN MFC, Instruction Manual

Page: 210 / 268

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WT.050.580.000.DE.IM.0714
Maintenance
MFC
7.
7.3 Maintaining membrane sensors
For the membrane sensor maintenance procedure, see 4.2.6
“Membrane sensors" on page 56.
“mA/V input module" on page 69
“Membrane sensor for chlorine dioxide CD7" on page 61
“Membrane sensor for ozone OZ7" on page 64
“Membrane sensor for total chlorine TC1 and TC1-S" on page 67
7.4 Maintaining ORP electrode
Depending on how dirty the sample water is, theORP electrode
must be cleaned at certain intervals. Unclean water causes the
measurement to be very slow. At the same time, the ORP 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, theORPelectrode 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.