Vaillant ecoTEC plus 418 - Page 33

You must treat the heating water
if the total volume of filling and top-up water ex-ceeds thrice the nominal volume of the heating
sys-tem over the service life of the system
or
if the limits given in the following tables are not ad-hered to.
Table 3.2 Guidelines for the heating water: Water hardness
Total heating
output
Total hardness at 20
l/kW for the smallest
boiler heating surface
(2)
Total hardness at > 20
l/kW < 50 l/kW for the
smallest boiler heating
surface (2)
Total hardness at > 50
l/kW for the smallest
boiler heating surface
(2)
kW
mol/m3
mol/m3
mol/m3
< 50
No requirement or < 3
(1)
2
0.02
> 50 to < 200
2
1.5
0.02
> 200 to <
600
1.5
0.02
0.02
> 600
0.02
0.02
0.02
1) with systems equipped with wall-hung boiler and systems with electric heating elements
2) of the specific system volume (nominal capacity in litres/heating output; in case of multiple
boiler systems the lowest individual heating output should be used) These data only apply up to
3x the system volume for filling and top-up water. Once this triple system volume is exceeded,
the water will have to be treated exactly the same as in case of exceeding the limit values given
in table 3.3 (softening, desalination, hardness stabilisation and desludging).
Table 3.3 Guidelines for heating water: Salinity
Heating water
qualities
Unit
Low-salt
Saline
Electric conductivity
at 25 °C
μS/cm
< 100
100-1500
Appearance
Free of sedimentary substances