Grunbeck Delta-p, Operation Manual

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12.3 Sodium content in the water
When softening water by 1 °dH (0.18 mmol/l), the sodium content increases by approx.
8.2 mg/l. The German Drinking Water Ordinance specifies that the sodium content of
drinking water must not exceed 200 mg/l. Select a soft water hardness with a sodium content
less than 200 mg/l.
The local water suppliers will inform you about the sodium content of your raw water.
Sample calculation:
Raw water hardness: 28 °dH (50 °f)
Sodium content in the raw water: 10.5 mg/l
Admissible increase of the sodium content by softening:
● 200 mg/l - 10.5 mg/l = 189.5 mg/l
● 189.5 : 8.2 = 23 °dH (41 °f)
The raw water hardness is allowed to be reduced from 28 °dH (50 °f, 5 mmol/l) to 5 °dH (9 °f,
0.9 mmol/l).
12.4 Hardness range
Recommendation soft water hardness
Soft water hardness Remark
3 °dH
5.3 °f
0.53 °mmol/l Minimum value as per DIN 12502 Corrosion
Protection.
4 – 6 °dH
7.1 – 10.7 °f
0.71 – 1.07 mmol/l Ideal soft water, highest comfort.