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2. INTRODUCTION
These systems come with a residual hardness regulator as
standard, which allows selecting the appropriate hardness for
your home.
Its friendly-use electronic programmer will allow you to put the
system into operation in an easy and fast manner.
2.1 What Is Hardness?
Hardness is the quantity of scaling salts present in water,
which are mainly composed of low solubility salts of calcium
and magnesium. The main salts causing hardness are listed
below:
Calcium bicarbonate:
Calcium chloride:
Calcium sulphate:
Magnesium bicarbonate:
Magnesium chloride:
Magnesium sulphate:
Ca(CO3H)
2
CaCl2
CaSO4
Mg(CO3H)
2
MgCl2
MgSO4
These salts, due to its chemical properties, have a tenden-
cy to precipitate, producing scale on pipes and obstructing
them as they accumulate. In the same way, hardness has a
high tendency to scale on electrical resistors from heaters
and to precipitate into heaters when temperature increases.
The combination of hard minerals and soap produces a soap
curdling. This soap curdling reduces the cleansing properties
of soap. Hard minerals precipitation builds a layer on cooking
utensils, connections and plumbing fixtures. It may even alter
the taste of food.
MAIN PROBLEMS
Precipitation on pipes, fixtures and appliances.
Precipitation on electrical resistors, increase on energy
consumption due to the generated isolation.
Higher consumption of soap and chemical products.
Reduction of the electrical appliances’ service life and
greater maintenance.
All these problems are solved when using a water softener,
since water obtained after being treated by the system is
completely free of scaling salts.
For the most part of Europe, hardness is indicated in French
hydrometric degrees, but there are also other measuring
units, according to each region.
Below are the most usual equivalences.
UNITS
1 ppm of Calcium
1 ppm of Magnesium
1 ppm of CaCO3
1º French (ºHF)
1º German (ºd)
1º English (ºe)
1 mmol/L
1 mval/L=meq/L
ppm of CaCO3
2,5
4,13
1
10
17,8
14,3
100
50
º French
0.25
0.413
0.1
1
1.78
1.43
10
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2.2 How Does Your System Work?
Water softening is carried out by means of an ion exchange
process. On this purpose, the system uses resins with the
chemical capacity of capturing Calcium (Ca) and Magne-
sium (Mg) ions and removing them from water.
When Calcium and Magnesium ions are captured by the
resin, two Sodium (Na) ions are released which, due to its
chemical properties, produce salts with a higher solubility
avoiding all hardness-related problems.
Therefore, when water gets softened, its sodium level in-
creases.
Further information on this procedure can be found in ‘Sec-
tion 2.8’.
ION EXCHANGE RESINS:
They are synthetic compounds, usually with an spherical
shape, able to capture certain chemical substances pre-
sent in water, which then exchanges for other substances.
Water softening uses strong cation resins, which are com-
posed of styrene copolymers and divinylbenzene with a
sulphur base.
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