Viessmann Vitoplex 200 Series Service Instructions Manual page 28

Water quality
Water quality requirements
Note
Observing the following requirements is necessary to
safeguard your warranty rights.
The warranty excludes damage due to corrosion and
scaling.
Heating systems with rated operating temperatures up to 100 °C (VDI 2035)
Water used in heating systems must meet the chemi-
cal values in the Drinking Water Ordinance [Germany].
If well water or similar is used, check its suitability
before filling the system.
Prevent excessive scale build-up (calcium carbonate)
on the heating surfaces. For heating systems with
operating temperatures up to 100 °C, Guideline
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. For further information, see the annotations to
Directive VDI 2035.
Total heating out- 50 to
>
put in kW
Total alkaline
earths in mol/m 3
Total hardness in
≤
°dH
The standard values assume the following:
■ The total volume of fill and top-up water is max. 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 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.
28
200 to
≤ > ≤ >
200 600
2.0 1.5 < 0.02
≤ ≤
11.2 8.4 < 0.11
≤
When designing the system, observe the following:
Install shut-off valves in each section. This prevents
■
the need for draining all the heating water in the case
of repairs or system expansion.
■ Install a water meter to record the amount of the fill
and top-up water. Enter the volume of fill water and
the water hardness into the boiler service instruc-
tions.
For systems with a specific system volume in excess
■
of 20 l/kW heating output (for multi boiler systems,
apply the output of the smallest boiler), apply the
requirements of the next highest category of total
output (in accordance with the table). In the case of
severe excess (
>
a total of alkaline earths of
600
Operating information:
■ Start the system gradually with a high heating water
flow rate, starting with the lowest boiler output. This
prevents localised concentration of limescale depos-
its on the boiler heating surfaces.
■ In multi boiler systems, start all boilers simultane-
ously to prevent the total amount of limescale depos-
its settling in the heat exchanger of just one boiler.
■ During expansion or repair work, only drain the nec-
essary sections.
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.
■ Check, clean and activate filters, dirt traps and other
blow-down or separating facilities in the heating
water circuit regularly after commissioning and in
new installations. Thereafter, this may be one as
required, depending on the type of water treatment
applied (e.g. water softening).
The build-up of limescale deposits on the heating sur-
faces will be minimised if these instructions are fol-
lowed.
50 l/kW), soften the water down to
3
0.02 mol/m .
≤