Technical Information, Water Treatment - Wolf MGK-130 Technical Manual And Installation Instructions

The use of chemical additives and softening using
single-stage ion exchangers is not permissible.
Permissible methods:
- Desalination via mixed bed cartridges: These are multi-
stage ion exchangers. We recommend, for example,
using GD/GDE cartridges from Grünbeck for the first
fill, and later as and when required
- Desalination via reverse osmosis
- Topping up with distilled water
Treating the heating water
We recommend a heating water pH value of between 6.5
and 9.0, also in mixed installations comprising various
materials.
Request a water analysis from the water utility. This
must test whether the total hardness is sufficiently low.
With specific system volumes V
kW, apply the next lower limit value from the following
table.
For multi-boiler systems, the output of the smallest boiler
must be specified.
Stage System Permissible
output total
in kW hardness
C in °dH
max
1* up to 50 2 - 17
2 50-200 2 - 11
3 201-600 2 - 8
4 > 600 2 - 3
Table: Maximum permissible total hardness. This
corresponds to the total of alkaline earths.
* Alternatively, the installation of a filter or a separating
facility in the heating return would also be adequate.
The total hardness must not fall below
NB
2 °dH.
Example:
System with a 170 kW boiler;
System volume V
V = 4000 l / 170 kW = 23.5 l/kW
A, specific
This is greater than 20 l/kW, therefore
Stage 3 must be selected. Both fill and
top-up water must be within the range of
2 to 8 °dH.
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Technical information, water treatment

greater than 20 l/
A, specific
Permissible Permissible
total total hardness
hardness C in mmol/l
max
C in g/m³
max
40 - 300 0.4 - 3
40 - 200 0.4 - 2
40 - 150 0.4 - 1.5
40 - 50 0.4 - 0.5
= 4000 l
system
If the total hardness is too high, some of the fill and top-
up water must be desalinated.
A % desalinated water should be added:
A = 100% – [(C – 0.1 °dH) / (C
max
C Maximum permissible total hardness
max
in °dH
C Total hardness of the untreated
DHW
DHW in °dH
We recommend allowing for the expected top-up water
during the first fill. Untreated DHW can then be added
later.
V = A x (V
treatment
In large systems in stage 4, the top-up water should
not be taken into account during the first fill.
V
treatment
Example:
System output = 170 kW;
System volume V
system
Volume of top-up water
V = 1000 l
top-up
Total hardness of the DHW C
Maximum permissible total hardness C
A = 100% - [(8 - 0.1) / (18.5 – 0.1)] x 100% = 100%
- 42.9% = 57.1%
57.1% of the fill and top-up water must be
desalinated.
V = 57.1% x (4000 l + 1000 l) = 2850 l
treatment
When filling the system, 2850 l of desalinated
water must be added. The system can then be
topped up to V with DHW.
max
When topping up, it is important to check regularly
that the permissible total hardness is not exceeded.
– 0.1 °dH)] x 100%
DHW
+ V )
system top-up
= A x (V )
system
= 4000 l;
= 18.5 °dH;
DHW
= 8 °dH
max
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