Water Softening System - Electrolux Diva Service Manual

6.5 WATER SOFTENING SYSTEM

6.5.1 SOFTENING PROCESS
If featured, this softening system is based on the use of resins (organic synthesis substances) and a
chemical process of ion exchange.
This exchange takes place rapidly, i.e. as soon as the water comes into contact with the resins.
The calcium and magnesium salts contained in the water are removed, while their sodium base is
created.
The exchange process takes place during every fill phase, each time water is introduced into the
circuit by energizing the solenoid valve.
6.5.1.1 SOFTENING CIRCUIT
The fill water from the solenoid valve (2/3), after filling the
regeneration chamber (7), continues its path until it reaches the resin
reservoir (9).
The water then slowly passes upwards through the resin bed, where it
is softened; from here, the water continues its route towards the sump.
Obviously, after a certain period, the resins lose their softening power
(i.e. are no longer able to perform the sodium exchange) because
they are saturated with calcium and magnesium. In this case, it is
necessary to regenerate the resins by introducing sodium chloride
(salt).
6.5.2 REGENERATION PROCESS
In order to regenerate the resins and restore their efficacy, it is necessary to use a salt (sodium
chloride) solution, which should be allowed to pass slowly through the resins or, preferably, left to soak
the resins for a period.
In this case, too, the ion exchange takes place. The sodium contained in the salt solution eliminates
the calcium and magnesium salts that have been deposited on the resins, which thus regain their
softening power.
The regeneration phase is performed at a pre-determined point in the washing cycle by energizing the
regeneration solenoid valve for a given time.
The quantities of water and salt used are optimized according to the level of regeneration selected by
the user, which in turn depends on the hardness of the water coming from the mains.
6.5.2.1 REGENERATION CIRCUIT
The volume of water utilized for the regeneration process depends on the
degree of inclination of the separation baffle (A).
The water is ducted through the separation baffle via an internal channel
which is open at one extremity.
The inclination of the separation baffle determines the quantity of water
used: as the baffle moves towards the horizontal position, more water is
used, since only the water above the overflow level is introduced.
When the regeneration solenoid (4) is energized, the volume of water
contained in the regeneration chamber (7) (280 cc max.) descends by
gravity into the salt reservoir; at this point, the internal valve (*) opens,
allowing the corresponding quantity of salty water to pass into the resin
reservoir (9).
After draining, the internal valve (*), which is no longer pressurized,
closes the circuit.
When the solenoid is de-energized, the salt solution remains in the resin
reservoir until the subsequent resin washing procedure is performed.
SOI/TD - PR 27/32
A
*
599 38 72-30