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Last change 10/2018 E-P | Subject to technical modifications
Appendices 2:
Calculation soft water capacity
Capacity of softener x S
L=
in m³ soft water
Local permanent hardness
L = soft water volume between two regenerations
S = Safety factor
0.9 for boiler water and RO
0.8 for strong fluctuating supply water hardness
The local permanent water hardness shall be determined and controlled by means of a test kit.
Type of plant
VAS
– CS
25-CS
1”
50-CS
1“
75-CS
1“
125-CS
1 ½”
150-CS 1
½”
200-CS 1
½”
250-CS
2”
375-CS
2”
600-CS
2”
Capacity
(m³ @ 300 ppm)
VAS
– CS - A
5.3
10.8
16.2
27.3
32.2
43.5
54.9
82.8
132.3
Economic salt use
VAS
– CS - B
3.9
7.8
11.8
19.9
23.4
31.6
39.9
60.2
96.2
Example:
A softener type VAS 50 - CS - B is installed. The supply water hardness is measured with 280 ppm.
7.8 m³ x 300 ppm x 0.9
L=
=
ca. 7.5 m³ soft water
(economic salt use)
280 ppm
The softener can produce ca. 7.5 m³ soft water when using the full salt volume.
Regeneration of softener has to be after three days if the daily consumption is ca. 2.5 m³.
