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UP 2.3-919
41
1. Measuring the drive potential
Procedure: Set the instrument switch to the 20 V DC range. Connect the
positive probe of the instrument to the anode and the negative one to the
storage tank.
Nominal value: M 2.3 V DC. Depending on the conductivity of the
water, drive potentials in the range between 2.3 and about 5 V are normal -
these figures are approximate values. Higher drive potentials are possible
when the water has a very low conductivity.
Deviations from nominal value: Higher drive potentials (up to 10 V) may be
a sign of uninsulated metallic heat exchangers. When the drive voltage is
practically zero, the cathodic corrosion protection is not operational. This
can be the case when the titanium anode and the storage tank are short-
circuited, e.g. as a result of sealing failure or of the anode being in contact
with fittings inside the tank.
2. Measuring the protective current
Procedure: Set the measuring instrument to the 200 mA or 20 mA range
and connect in series with the circuit between plug-in potentiostat and tank
or alternatively between plug-in potentiostat and anode.
Nominal value: With standard enamelling and absence of supplementary fit-
tings, low, single-digit mA values are typical for the usual drinking water
qualities. The actual values are also dependent on the tank size.
Deviations from nominal value: High mA values, especially in the double-
digit range, may be a sign of large defective spots or short-circuited non-
enamelled fittings with insufficient electrical insulation. If the protective cur-
rent is, however, equal to zero (mA), the cathodic corrosion protection is
out of order. Check the connecting cable and the contacts.
3. Checking the polarity
Procedure: Connect the positive probe of the instrument with the anode
and the negative one with the tank.
Nominal value: Drive potential >/= + 2.3 V = (plus!). The sign indicated by
the instrument must be positive (plus).
Deviations from nominal value: When the value is negative (e.g.: -2.5 V),
the polarity is incorrect. Risk of increased tank corrosion. Switch off the
CORREX
®
UP system immediately and contact the storage tank after-sales
service.
0425_Bed.anl_UP_Innen_gesamt.qxd 25.05.2006 19:15 Seite 41
