Water Quality Requirements - Viessmann VITOCROSSAL 300 Type CT3 Service Instructions Manual

Water quality requirements

Note
Observing 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, the VDI Directive 2035
sheet 1 "Prevention of heating system damage – scaling in DHW and hot water heat-
ing systems" applies [in Germany] together with the following standard values (see
also the relevant explanations in the original directive).
Total output
kW
> 50 to ≤ 200
> 200 to ≤ 600
> 600
The standard values assume the follow-
ing:
■ The total volume of fill and top-up
water during the system's service life
will not exceed three times the water
content of the heating system.
■ 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 implemented.
Total of alkaline earths
3
mol/m
≤ 2.0
≤ 1.5
< 0.02
Total hardness
°dH
≤ 11.2
≤ 8.4
< 0.11
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 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.
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