4.2 Necessity of Make-up Water Treatment
In heating systems with a constructive oxygen ingress a low electrical conductivity of the heating water should
be realized, as corrosion processes are slowed down by a low electrical conductivity. Since an elector is used
in most cases in systems with a high oxygen input, we recommend, along with the installation of the elector, a
reduction in electrical conductivity to a level of 50 - 200 μS / cm.
The need for make-up water treatment can also arise from the requirements of other component manufacturers,
or whenever a guideline, such as VDI 2035, must be observed.
4.3 Method of Make-up Water Treatment
If the filling water has to be treated, only a full or partial deionization of the filling water of heating systems
should be used in combination with an elector. A residual conductivity of 50 - 100 μS / cm must be maintained.
When using an elector reaction device, the filling water should not be treated by softening with ion exchange. A
reduction of the total hardness of the water can also be achieved by a partial desalination, if the system is filled,
for example with 20% of the system volume with tap water and 80% of the system volume with deionized water.
4.4 Use fo Antifreeze Agents
In combination with an elector, classic antifreezes should not be used as these agents usually contain chemical
inhibitors. These inhibitors can completely stop the function of the elector.
If a heating system are subject to freeze, ethylene glycol with the quality notation „chemically pure“ can be used
in addition to the use of an elector.
It should be noted that the aging of ethylene glycol causes the formation of acids that are bound by the elector.
At very high temperatures, acid formation may exceed the level of buffering by the elector, allowing temporary
low pH. This can be remedied by installing a larger elector reaction tank.
When using antifreeze, the antifreeze as well as the pH of the water should be checked annually.
4.5 Influence of the Electrochemical Water Treatment on the Total Hardness
Experience has shown that, depending on the water composition, the overall hardness of the system water
drops slightly as a result of the increase in the pH value and the associated precipitation of calcium carbonate in
the elector reaction devices.
Any available free carbonic acid can be bound as magnesium hydrogen carbonate by the magnesium ion
electrochemically generated in the elector. An uncontrolled increase in hardness is not to be feared, as there is
no more free carbonic acid in the heating water from a pH value of 8.2. In contrast to calcium carbonate, the
good solubility of magnesium carbonate does not cause an additional risk of damage caused by scaling.
To avoid damage caused by formation of limescale, a heating system should not be filled with water that has a
total hardness> 16.8 ° dH.
Page 10
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elector – Electrochemical Water Treatment for Heating Systems
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