Insulation Testing - Magontec CorroScout 500 Notice D'utilisation

Operating Instructions CorroScout
With reversed polarity of positive and negative (red and black), the
typical reverse voltage now applies, display approximately 500 mV.
Testing the correct polarity (anode: + / tank: -) is also possible with
the ' drive potential measurement (see below).
Information: Not all types of CORREX
are equipped with reverse polarity detection. Thus, it is possible that
the results described, such as the diode reverse voltage cannot be
found on some types as no diode is installed.

4.4 Insulation testing

During the production process of the tank unavoidable flaws in the
enamel surface occur. Therefore anodes are used for the cathodic
corrosion protection. According to standards regulations, the total
surface of the enamel flaws should be less than 7 cm² per m² of
enamelled surface.
Caution: Flat bundle tube heat exchangers or tube-fin heat exchan-
gers of copper can easily have surface areas of 1 m² or more. With
non-insulated installation of corresponding heat exchangers in direct
contact with the tank material, the heat exchanger acts as a enor-
mous flaw area deteriorating the cathodic protection conditions con-
siderably.
For this reason, the installation of corresponding non-enamelled heat
exchangers is preferably carried out with the use of a so-called
potential balance resistors with an ohmic resistance in the range of
approximately 600
avoids the undesired current leakage corrosion.
In order to test for sufficient insulation of the heat exchanger, the
water must be drained until the heat exchanger is dry.
Measurement is carried out as follows:
1. Set CorroScout
2. Contact one of the two measuring leads of the CorroScout
with the pipe outlet of the heat exchanger and the other measuring
lead with the wall.
3. The actual insulation resistance is shown on the display. If the
value is substantially less than 500
region, then the insulation must be checked.
30
® 500
. This usually ensures sufficient insulation and
® 500 to the "Isolation" (Insulation) measuring range.
® impressed current anodes
, possibly even in the 2 digit
® 500