Magontec CORREX MP 2.3-900 Notice D'utilisation page 41

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
fittings, 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
current 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 ® MP 2.3-900 system immediately and contact the storage tank
after-sales service.
4. Checking the insulation
a) Installed, non-enamelled electrical tubular heating elements or heat
exchangers
b) Titanium anode
Procedure: Set the measuring instrument to the resistance range. Drain off
the water to prevent indirect electrical contact via the water. Connect the
probe leads of the instrument (a) with the tubular heater and the enamelled
tank, or (b) with the titanium anode and the enamelled tank. Measure the
electrical resistance.
Operating Instructions CORREX ® MP 2.3-900
41