Checking The Water Hardness; Water Hardness Test Procedure; Result; Conversion Of Water Hardness - Grundfos Selcoperm 98842487 Bedienungsanleitung

3. Checking the water hardness

A properly functioning water softener is crucial for
the efficiency and longevity of the Selcoperm
system. High levels of calcium carbonate in the
electrolyte lead to a visible precipitation on the
electrodes of electrolyser cell.
The water hardness test is a drop test. The hardness
is determined by counting the drops of reagent, until
the colour changes.

3.1 Water hardness test procedure

1. Take a sample from the soft water sample valve
at the Selcoperm system.
2. Fill the sample container to the 5 ml mark.
3. Hold the reagent bottle vertically. Add the reagent
drop by drop while swivelling the sample
carefully, until its colour turns from red to green.
– Count the number of drops. One drop equates
to one degree of total water hardness.

3.2 Result

• If the sample turns green with one drop of
reagent, the water is soft.
– The water softener if functioning properly.
• If the sample turns red and requires more than
one drop to turn green, the water is not soft.
– The water softener needs regeneration or the
resin beads must be replaced.

3.3 Conversion of water hardness

°d °e °f
1 1.3 1.8
2 2.5 3.6
3 3.8 5.4
4 5.0 7.1
5 6.3 8.9
6 7.5 10.7
7 8.8 12.5
8 10.0 14.3
9 11.3 16.1
10 12.5 17.8
8
mg/l mg/l
mmol/l
CaO CaCO
3
10 18 0.18
20 36 0.36
30 54 0.54
40 71 0.71
50 89 0.89
60 107 1.07
70 125 1.25
80 143 1.43
90 161 1.61
100 178 1.78
4. Checking the specific gravity (SG)
of the electrolyte
SG is the specific gravity of the electrolyte entering
the electrolyser cell.

4.1 SG test procedure

1. Flush a clean and dry measuring cylinder with
electrolyte from the electrolyte sample valve.
2. Fill the measuring cylinder with a sample from the
electrolyte sample valve.
3. Place the hydrometer in the measuring cylinder.
4. Take the reading from the hydrometer.
5. Checking the temperature of the
NaClO solution
1. Take a sample from the NaClO solution sample
valve at the Selcoperm system.
2. Place the thermometer in the sample and take
the reading.
– The reading should not exceed 40 °C.

6. Spare parts

Description
Hydrometer
Thermometer
Stirring rod
Syringe assembly with 3-way
valve, 1.25 ml
Total hardness test kit
Set of 100 Acidifying GP tablets
and 100 Chlorine HR tablets
Titrant cartridge with 20 ml of 2N
sodium thiosulfate solution
(Na S O )
2 2 3

7. Disposal

The used analysis sample can be flushed down the
drain with tap water. Unused, expired reagent must
be disposed of according to local regulations.
Product
number
98503876
98708008
95727771
98948744
98948745
98144705
98948756
Subject to alterations.