Viessmann VITOMAX 200-HS Operating And Service Instructions page 24

Water quality
Water quality for steam boiler systems
Permiss. oper-
ating pressure
Phosphate
(PO )
4
Silicic acid
(SiO ) *4
4
Note
The addition of phosphate is recommended, but is not always essential.
Conversion: 1 mol/m
Operation with salt-free boiler feedwater is also possible as an alternative to operation
with saline boiler feedwater.
*4 If phosphate is used, higher PO
sideration of all other values, e.g. with balanced or coordinated phosphate treat-
ment. (See section "Conditioning")
24
Feedwater conductivity >
bar > 0.5 to 20
mg/l
mg/l
3
= 5.6 °dH; 1 °dH = 0.179 mol/m
4
(cont.)
30 µS/cm
10 to 20 10 to 20
Pressure-dependent, see the diagrams on
pages 25 and 26
concentrations are permissible, subject to con-
Feedwater conduc-
tivity ≤ 30 µS/cm
> 20
3
; 1 mval/kg = 2.8 °dH
> 0.5
6 to 15