20
Note
Observing the following requirements is necessary to
safeguard your warranty rights.
The 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, Directive
VDI 2035 Part 1 "Prevention of damage in water heat-
ing installations - Scale formation in domestic hot
water supply installations and water heating installa-
tions" applies together with the following standard val-
ues. See also the explanations in the original text of
the Directive.
Total heating output
kW
Total alkaline earths
mol/m
3
Total hardness
°dH
> 50 to ≤ 200 ≤ 2.0 ≤ 11.2
> 200 to ≤ 600 ≤ 1.5 ≤ 8.4
> 600 < 0.02 < 0.11
The standard values assume the following:
■
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 out-
put of the smallest boiler.
■
All measures to prevent corrosion on the water side
in accordance with Directive VDI 2035 Part 2 have
been implemented.
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 standard value.
■
Higher fill and top-up water volumes are expected.
■
The specific system volume is greater than 20 l/kW
heating output. In multi boiler systems, apply the out-
put of the smallest boiler.
■
In systems > 50 kW, install a water meter to capture
the amount of fill and top-up water. Enter the volume
of fill water and the water hardness into the boiler
maintenance checklists.
■
For systems with a specific system volume in excess
of 20 l/kW heating output (in multi boiler systems
apply the output of the smallest boiler), apply the
requirements of the next higher category of total out-
put (in accordance with the table). In the case of seri-
ous deviations (> 50 l/kW) soften down to a total of
alkaline earths ≤ 0.02 mol/m
3
.
Operating information:
■
During expansion or repair work, only drain the nec-
essary pipework sections.
■
Check, clean and activate filters, dirt traps and other
blow-down or separating facilities in the heating
water circuit more frequently after commissioning or
in case of new installations, later on subject to the
water treatment applied (e.g. water softening).
■
No further steps are required during commissioning
if you fill the heating system with fully softened
water.
If the heating system is not filled with fully soft-
ened water, but with water that meets the require-
ments in the above table, also observe the follow-
ing during commissioning:
■
Commission the system step by step, starting with
the lowest boiler output and a high heating water
flow rate. This prevents localised concentration of
limescale deposits on the boiler heating surfaces.
■
In multi boiler systems, start all boilers simultane-
ously to prevent the entire limescale deposit settling
in the heat exchanger of just one boiler.
■
Where water treatment is required, treat even the
first fill of the heating system prior to commissioning.
This also applies to any subsequent filling, e.g. when
adding top-up water or after a repair, or for any sys-
tem expansion.
The build-up of limescale deposits on the heating sur-
faces will be minimised if these instructions are
observed.
Water quality
Water quality requirements
5692 701 GB
Appendix
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