Viessmann VITOCROSSAL 200 Service Instructions Manual page 88

Water quality requirements
■ In systems > 50 kW, install a water
meter to record the volume of the 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 vol-
ume in excess of 20 l/kW heating out-
put (in multi boiler systems apply the
output of the smallest boiler), apply the
requirements of the next higher cate-
gory of total output (in accordance with
the table). In the case of severe
excess (> 50 l/kW), soften the water
down to a total of alkaline earths of
3
≤ 0.02 mol/m .
Operating information:
■ During expansion or repair work, only
drain the necessary sections.
■ Check, clean and activate filters, dirt
traps and other blow-down or separat-
ing facilities in the heating water circuit
more frequently after commissioning
or new installations; later on do so sub-
ject to requirements in line with 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 softened water, but with water
that meets the requirements 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 a localised concentra-
tion of limescale deposits on the boiler
heating surfaces.
88
(cont.)
■ In multi boiler systems, start all boilers
simultaneously to prevent the entire
limescale deposit settling in the heat
transfer area 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. after repairs or after system
expansion, and for all amounts of top-
up water.
The build-up of limescale deposits on the
heating surfaces will be minimised if
these instructions are observed.
If limescale deposits have formed
because of a failure to observe the
requirements of guideline VDI 2035 the
service life of the installed heating appli-
ances will, in most cases, already have
been reduced. Removing the limescale
deposits is one option for restoring
operational viability.
This measure must be carried out by a
specialist. Inspect the heating system for
possible damage prior to returning it into
use. It is essential that the faulty operat-
ing parameters are corrected to prevent
renewed formation of excessive scale
deposits.