18
JUDO i-soft@home 5
Operation
5.4.4 Desired water hardness set-
ting limitations
The water softening system control unit
checks if the desired water hardness is cor-
rectly set.
1. Limitation due to the mixing valve
setting range:
The desired water hardness can be set be-
tween 1 °dH and half the value of the un-
treated drinking water ha2 °dH.
Example: Untreated drinking water hard-
ness = 18 °dH
Desired water hardness setting:
1 to 11 °dH
The desired water hardness cannot be set to
a higher value.
The maximum hardness that can be set via
the menu with the
key is limited to the val-
ue calculated by the control unit. Higher val-
ues are not possible.
2. Limitation due to the maximum value
for sodium in the drinking water:
After the softening, the sodium concentra-
tion in the mixing water increases, depend-
ent on the raw water hardness and the set
desired water hardness.
According to current national drinking water
legislation, the limit value for sodium in
drinking water is 200 mg/l. Mineral and table
water are not affected by this. Their limit val-
ues are much higher, partially greater than
1000 mg sodium per litre.
If the calculated total sodium content ex-
ceeds the valve permitted by the drinking
water legislation of 200 mg/l, then it can be
corrected by increasing the desired water
hardness.
Based on the raw water hardness and de-
sired water hardness, the electronics deter-
mine the sodium content. The electronics do
not take into account the sodium content of
the raw water. If the limit value of the drink-
ing water ordinance is exceeded, the follow-
ing messages appear on the display:
Calculation of the sodium content
°dH
Raw water hardness (ask
the water supply company
or measure with hardness
measuring instrument)
-
°dH
Residual hardness (meas-
ured value)
=
°dH
Difference in water hardness
×
8.2 mg Na
+
/l × °dH
Na ions exchange value
=
mg/l
Increase of the sodium con-
tent by softening
+
mg/l
sodium already present in
the raw water (ask the water
supply company)
=
mg/l
Total sodium content in the
mixing water
Example calculation of the sodium con-
tent
20 °dH
Raw water hardness
- 8 °dH
Residual hardness
= 12 °dH
Difference in water hardness
× 8.2
= 98 mg/l
Due to softening:
+ 10 mg/l
From water supply company
= 108 mg/l
In total
Attention!
Sodium limit val
