Design Information; Water Treatment - Wolf CGB-75 Installation And Technical Manual

The addition of chemicals or descaling using single-stage ion
exchangers is not permissible, otherwise system damage due
to water leaks may occur.
Permissible methods:
- Desalination using 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
18

Water treatment

necessary
14
10
6
No water treatment
necessary
2
200 400 600 800
System volume in l
Figure: Water treatment
Treating the heating water in accordance with VDI 2035:
We recommend a heating water pH value of between 6.5 and
8.5, also in mixed installations with various materials.
Request a water analysis from the water utility. This must test
whether the total hardness is sufficiently low. If the specific
system volume is greater than V
smallest limit value must be taken from the following table.
For multi-boiler systems, the output of the smallest boiler must
be specified.
Stage System Permissible
output total hardness
in kW c in °dH
max
1 up to 50
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
Please note: The total hardness must not fall below 2
°dH.
Example: System with a 170 kW boiler;
V = 4000 l / 170 kW = 23.5 l/kW
A, specific
This is greater than 10 l/kW, therefore stage 3 must be
selected. The fill and top-up water must be in the range of
2 to 8 °dH.
36
Design information, water treatment
CGB-75
CGB-100
1000 1400
1200 1600 1800
10 l/kW, the next
A, specific
Permissible Permissible
total hardness total hardness
c in g/m³ c in mmol/l
max max
No requirements
40 - 200 0.4 - 2
40 - 150 0.4 - 1.5
40 - 50 0.4 - 0.5
system volume V = 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
c Maximum permissible total hardness in °dH
max
c Total hardness of the untreated potable water
DHW
in °dH
We recommend allowing for the expected top-up water during
the first fill. Untreated potable water can then be added later.
2000
In large systems in stage 4, the top-up water should not be
taken into account during the first fill.
Example:
System output = 170 kW;
System volume V
Volume of top-up water
V = 1000 l
top-up
Total hardness of the potable water 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
potable water.
When topping up, it is important to check regularly that the
permissible total hardness is not exceeded.
– 0.1 °dH) / (C – 0.1 °dH)] x 100%
max DHW
V = A x (V + V
treatment system top-up
V = A x (V )
treatment system
= 4000 l;
system
DHW
max
)
= 18.5 °dH;
= 8 °dH
with
max
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