Automatic Cycle; Turbidity Sensor; Calculating The Degree Of Soiling; Determination Of The Load - Electrolux EDW 1500 - 1510 Service Manual

8 Automatic cycle

8.1 Turbidity sensor

Certain models which feature the turbidity sensor may also feature a special
"automatic" programme which optimizes the cycle according to the size of the load
and the degree of soiling. This sensor is positioned externally to the sump, in direct
contact with the water.
A single container houses the NTC sensor (for control of the washing temperature)
and the infra-red opto-electronic sensor, which controls the turbidity of the water and
therefore the degree of soiling that it contains.
8.1.1

Calculating the degree of soiling

Measurement of the level of turbidity is
performed during the cold pre-wash. The
photoemitting diode, which is powered by the
circuit board (connector G7), transmits a beam
of light to the photoreceiver. The circuit of the
photoreceiver (connector G8 on the circuit
board - G6 is the common contact) is traversed
by a certain current whose intensity is
proportional to the quantity of light received (i.e.
inversely proportional to the level of turbidity).
The microprocessor measures the signal
present in the circuit, and can thus determine
the most appropriate cycle according to the
quantity of soiling present in the water.
8.1.2

Determination of the load

The quantity of dishes in the load (full load or 1/2
load) is determined during the initial heating
phase during washing by controlling the rate at
which the temperature of the water increases
(NTC sensor, connector G5).
Full load: when the inclination of the curve is
below a certain threshold which is memorized
as standard.
Half load: when the inclination of the curve is
above the standard threshold.

8.2 Automatic Programme

The table below shows the variations in the programme phases according to the type of soiling and the size
of the load.
Type
Heavy
Load
soil
Full Yes
Full No
Half Yes
Half No
SOI/TD - PR
Pre-wash Wash
68º C
55º C
Cold
55º C
50º C
temperature
Programme phases
First rinse Second rinse
Cold
Cold
26
1/2 load
full load
Hot rinse
68º C
no
599 36 01-86
threshold
time
Drying
24 min.