Viessmann VITOCROSSAL 300 Service Instructions Manual page 35

Water quality requirements
Water quality requirements
Note
Observing the following requirements is
necessary to safeguard your warranty
rights.
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 guideline 2035 sheet
1 "Prevention of heating system damage – scaling in DHW and hot water heating
systems" applies [in Germany], together with the following standard values (see also
the full explanations in the original guideline).
Total heating output
kW
≤ 50
> 50 to ≤ 200
> 200 to ≤ 600
≤ 600
The standard values assume the follow-
ing:
■ The total volume of fill and top-up
water will not exceed three times the
water content of the heating system
during its service life.
■ The specific system volume is less
than 20 l/kW heating output. In multi
boiler systems, 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.
The warranty excludes damage due to
corrosion and scaling.
Total alkaline earths
mol/m 3
≤ 3.0
≤ 2.0
≤ 1.5
< 0.02
Soften the fill and top-up water in heating
systems operating under the following
conditions:
■ The total of alkaline earths in the fill
and top-up water exceeds the stand-
ard value.
■ Higher fill and top-up water volumes
are expected.
■ The specific system volume is higher
than 20 l/kW heating output. In multi
boiler systems, apply the output of the
smallest boiler.
Total hardness
°dH
≤ 16.8
≤ 11.2
≤ 8.4
< 0.11
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