139
Note
Maintaining the following requirements
is necessary to safeguard your warranty
rights.
The manufacturer's warranty excludes
damage due to corrosion and scaling.
Prevention of damage due to scaling
Prevent excessive scale build-up (calcium carbonate) on the heating surfaces. For
heating systems with operating temperatures up to 100 °C, VDI Directive 2035 Sheet
1 "Prevention of damage to hot water heating systems – scaling in DHW and hot
water heating systems" applies [in Germany] together with the following standard
values (see also the corresponding explanations in the original text of the Direc-
tive):
Total output
kW
Total of alkaline earths
mol/m
3
Total hardness
°mmol/l
≤ 500
≤ 3.0
≤ 16.8
> 50 to
≤
200
≤ 2.0
≤ 11.2
> 200 to
≤
600
≤ 1.5
≤ 8.4
> 600
< 0.02
< 0.11
The standard values assume the follow-
ing:
■ The volume of fill and top-up water of
the heating system during its service
life will not exceed three times the
water content of the heating system.
■ The specific system volume is less
than 20 l/kW output. In multi boiler sys-
tems, apply the output of the smallest
boiler.
■ All measures to prevent corrosion on
the water side in accordance with
VDI 2035 sheet 2 have been imple-
mented.
Soften the fill & top-up water in heating
systems operating under the following
conditions:
■ The total of alkaline earths in the fill &
top-up water exceeds the standard
value.
■ Higher fill & top-up water volumes are
expected.
■ If the specific system volume is in
excess of 20 l/kW output. In multi
boiler systems, apply the output of the
smallest boiler.
Water quality requirements
5692 860 GB
Summary of Contents for CU3A
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