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We reserve the right to modify technical specifications without prior notice.
83050800aUK – Translation of the operating manual
© Alpha-InnoTec GmbH
Corrosion – an underestimated problem
vdI 2035, part II, deals with the problem of corrosion.
softening the heating water can prove to be insufficient.
The pH value can significantly exceed the limit of 10.
pH values higher than 11 can set in, which even damage
rubber seals. The vdI 2035, part 1 guidelines are fulfilled;
however, vdI 2035, part 2 suggests a pH value between
8.2 and maximum 10.
If aluminium materials are used, which is the case in
many modern heating systems, a pH value of 8.5 must
not be exceeded! because otherwise there is a threat of
corrosion – aluminium is attacked without the presence
of oxygen. Therefore, apart from softening the heating
fill and make-up water, the heating water should also
be appropriately conditioned. This is the only way
to comply with the vdI 2035 requirements and the
recommendations and installation instructions of the
heat pump manufacturer.
part 2 of vdI 2035 also refers to the reduction in total
salt content (conductivity). The risk of corrosion is far
lower if deionised water is used than is the case if the
system is operated with salty, i.e. softened water.
Even if drinking water has been softened beforehand,
it contains dissolved, corrosive salts, which act as
electrolytes due to the use of different materials in the
heating system and thus accelerate corrosion processes.
This can ultimately result in pitting.
on the safe side With loW-salt operation
The problems listed above do not occur at all with low-
salt operation, as the heating water contains neither
corrosive salts such as sulphates, chlorides and nitrates
nor alkalising sodium hydrogen carbonate. The corrosive
properties of deionised water are very low and in
addition, scale cannot form in the boiler. This is the
ideal approach for closed heating circuits, in particular,
because low oxygen input into the heating circuit can
also be tolerated.
In general, when the system is filled with deionised
water, the pH value sets itself within the ideal range due
to internal alkalinisation. If necessary, a pH value of 8.2
can be very easily alkalised by adding chemicals. In this
way, optimum protection of the entire heating system is
achieved.
monitoring
Analytical recording and monitoring of the relevant
water values and the added conditioning substances
is of decisive importance. Therefore, they should
be monitored regularly using appropriate water test
equipment.
Important
before flushing and filling the heating circuit,
the drain pipe of the safety assembly must be
connected.
Flush the heating circuit thoroughly…
note.
Flush heat pump and heating circuit for about
5 minutes.
Fill the heating circuit…
bleed (vent) the heating circuit.
Cleaning and flushing unit Components
CautIon!
unit components may be cleaned
and flushed only by customer service
personnel authorised by the manufacturer.
only use liquids recommended by the
manufacturer.
after flushing the condenser with chemical
cleaning agent, any residues must be
neutralised and the system thoroughly
flushed with water. always note and follow
the technical data of the respective heat
exchanger manufacturer.
