Asko DW20.1, Service Manual

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Single valve
The single valve consists of a draw magnet and a
valve seat.
Water softener valve
The water softener valve consists of two parallel-
connected valve seats, each with a draw magnet.
One part is used for regeneration of the water
softener (salt intake). An additional flow restrictor,
which maximizes the flow to 0.5 l/minute, is
located in the outlet from the water softener valve.
The other part is used for the regular water intake,
with the flow sensor connected after it.
Circulation pump
The circulation pump consists of an asynchronous
motor, a pump part and a condenser.
Spray arm divider
Certain machines are equipped with a spray arm
divider. The spray arm divider consists of a
synchronous motor that via a set of gears rotate a
valve-disc. A damper distributes the water from
the circulation pump to the upper and lower spray
arms in a different quantity and at a different
pressure. The motor/gearbox also causes a cam
with four different step times to rotate. A contact
detects the cam (step time) and provides the
control unit with feedback about the current
position when setting the desired spray arm status.
Note that the spray arms never rotate
simultaneously. The following spray arm statuses
are encountered:
•
Upper spray arm half or full pressure
• Lower spray arm half or full pressure
Depending on the programmeme, items being
washed and options, the spray arms will be
regulated with a varying interval and spray
pressure.
Machines with no spray arm divider have a
water distributor instead. This directs the water
to both spray arms. The spray arms always
rotate simultaneously.
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2.4 Functional description of components
A description of the function and specification of
the different electrical components is given here.
Certain components are only included in highly
specified machines or on individual markets.
Inlet valve/Flow valve
Available in single, safety and water softener
valve models.
A filter which traps particles is located in the
valve. Situated after this is a flow restrictor,
which maximizes the flow to 4 l/min. The valve
opens at water pressures exceeding 0.3 bar and
gives full flow at ca. 1 bar. The flow meter is
situated on the valve outlet, where it is secured
with a clip.
Flow sensor
The flow sensor is used to regulate the water
intake so that the correct water volume is
admitted regardless of the water pressure. There
is also the possibility of switching the machine
over to time-controlled water intake.
The flow sensor consists of a rotor containing a
magnet and a counterweight, which are caused
to rotate by water flowing through. Situated
externally on the flow sensor housing is a sensor,
a so-called reed switch, of which the contact is
closed every time the magnet passes. The
number of pulses from the sensor is proportional
to the volume of water flowing through.
Output signal: 210 pulses/litre
Safety valve
The safety valve consists of two mutually indepen-
dent valve seats, which are operated by two draw
magnets. The valve seats are connected in series.
This provides double reliability. The draw magnets
are also electrically connected in series, which
means that the magnet’s rated voltage is half the
mains voltage (e.g. 120 V valve = 2 x 60 V coils)