Design Information; Water Treatment - Wolf CGB-75 Assembly And Operating Instructions Manual

Before commissioning, the system must be thoroughly
cleaned / flushed through and a sludge filter (5 μm), e.g. Wolf
accessories, installed in the return and in direct proximity to
the boiler.
The filling and supplementary water may be treated only by
means of a desalting procedure. The degree to which water
treatment is necessary can be taken from the 'Water treatment
diagram' and the 'Maximum permissible total hardness table'.
The total degree of hardness of the system water may not fall
below 2 °dH; this corresponds to a conductance of ≈ 60 μS/
cm. The max. permissible total degree of hardness and the
corresponding max. conductance are system-specific and must
be calculated (see also the 'Table maximum permissible total
hardness'). To this end the saline-free water (conductance <=
30 μS/cm) must be mixed with untreated potable water. The
addition of chemical agents as well as lime elimination via
single-stage ion exchangers is not permissible, since otherwise
device damage can occur leading to the escape of water.
We recommend regular emptying of the sludge filter and the
maintenance of a system logbook.
Permissible methods:
- Deionisation via mixed-bed cartridges. These are multi-
stage ion exchangers. We recommend cartridges from the
Grünbeck or Judo companies for the initial filling and later
if required.
- Deionisation by reverse osmosis
- Topping up with distilled water
Total hardness /
total alkaline earths
[kW] [°dH]
1* < 50 2 - 16,8*
2 50-200 2 - 11,2
3 200-600 2 - 8,4
4 >600 2 - 3
*) for circulating water heaters (<0.3 l/KW) and systems with electrical heating elements
Gradual tightening of the specifications due to the specific system volume
(V = system volume / lowest individual power setting) and the total heating power
sys
The total filling quantity of water over the lifetime of the appliance may not exceed three times the nominal volume of the heat-
ing system.
Warning: the total hardness may not fall below 2 °dH
3062555_201507
Water treatment planning notes
Limit values in relation to the specific system volume V
(V = system volume / lowest individual power setting)
sys
Conversion of total hardness: 1 mol/m³ = 5.6 °dH
V ≤ 10 l/kW
sys
conduct-
ance
[mol/m³] cond.
[μS/cm]
0,36 - 3,0* 60 - 500
0,36 - 2,0 60 - 300
0,36 - 1,5 60 - 200
0,36 - 0,54 60 -100
18

Water treatment

necessary
14
10
6
Water treatment unnecessary
2
200 400
Diagram: water treatment
Treatment of the heating water based on VDI 2035:
We recommend a pH value of between 8.2 and 8.5 for the
heating water also in the case of combined installations of
different materials.
A water analysis must be requested from the water supply
company in order to check whether the total hardness is low
enough.
With a specific system volume V
smaller value from the following table must be applied, with
V >= 20 l/KW the next-but-one smaller value and with
sys,specific
V >= 40 l/KW the smallest value.
sys,specific
With a specific system volume of >50 l/KW the total degree
of hardness must be adjusted to 2-3 °dH using a desalting
process. This corresponds to a conductance of 60 - 100 μS/cm.
If the boiler is integrated into the system without a low-loss
header, the total hardness must be adjusted to 2 - 3 °dH
(conductance = 60 - 100 μS/cm).
V > 10 l/kW and < 40 l/kW
sys
Total hardness / conduct-
total alkaline earths ance
[°dH] [mol/m³] cond.
[μS/cm]
2 - 11,2 0,36 - 2,0 60 - 300
2 - 8,4 0,36 - 1,5 60 - 200
2 - 3 0,36 - 0,54 60 -100
2 - 3 0,36 - 0,54 60 -100
1000 1400
600 800 1200 1600
System volume in l
>= 10 l/KW the next
sys,specific
Sys
V ≥ 40 l/kW
sys
Total hardness /
total alkaline earths
[°dH] [mol/m³]
2 - 3 0,36 - 0,54
2 - 3 0,36 - 0,54
2 - 3 0,36 - 0,54
2 - 3 0,36 - 0,54
CGB-75
CGB-100
1800 2000
conduct-
ance
cond.
[μS/cm]
60 -100
60 -100
60 -100
60 -100
37