Viessmann VITOPEND 222 WHSA Datasheet page 31

Design information
Water quality/Frost protection
Unsuitable fill and top-up water increases the level of deposits
and corrosion and may lead to boiler damage.
& Thoroughly flush the entire heating system prior to filling it with
water.
&
Only use fill water of potable quality.
&
Soften fill water with a hardness above 3.0 mol/m
small softening system for heating water (see the Viessmann
Vitoset pricelist).
Drinking water quality
From a water hardness above 3.58 mmol/l and higher, we recom-
mend the use of a water treatment system in the cold water sup-
ply.
Secondary side connection to the Vitopend 222
The Vitopend is not suitable for use in conjunction with zinc-pla-
ted/galvanised pipes.
Sizing the diaphragm expansion vessel for heating water
A diaphragm expansion vessel is integrated into the Vitopend:
Inlet pressure 0.75 bar
Blow off pressure 3.0 bar
Terminal pressure 2.5 bar
Capacity 8 litres
Vitopend content 1.2 litres
When making the water connections, check that the size of the
expansion vessel matches the system conditions.
Install a second expansion vessel on-site if the integral expansion
vessel is not large enough.
The following steps will enable you to make a rough check.
A Panel radiators
B Convector heaters
Calculating expansion factor Af
Average heating water temp.
[°C]
50
60
70
80
VITOPEND 222
(cont.)
3
, e.g. with the
Expansion factor
Af
0.0121
0.0171
0.0282
0.0295
& An antifreeze additive suitable for heating systems can be
mixed with the fill water. The antifreeze manufacturer must ver-
ify its suitability.
For further details, see the VdTÜV datasheet 1466.
&
For initial start-up or systems with a volume in excess of 20
litres/kW, observe VDI 2035 and the technical guide "Standards
for water quality".
Note
Adjust the inlet pressure to the static head prior to filling the sys-
tem.
Example:
A height differential of 5 m within the heating system results in an
inlet pressure of 0.5 bar.
Calculating the heating system volume
C Radiators
D Underfloor heating
Calculating pressure factor f
Inlet pressure System height
[bar] [m]
1.0 10.0
0.75 7.5
0.5 5.0
Pressure factor
f
2.4
2.1
1.8
VIESMANN
31