Automatic Water Entry System (A.e.a); Flowmeter; Pressure Switch - LAVAZZA LB 4712 Maintenance Manual

1.3.6.3. Automatic water entry system (A.E.A)

The automatic water entry system checks the water level
in the boiler.
The system is composed of:
- a probe inserted in the boiler (a) which is composed of
a stainless steel rod;
- an electronic control unit (B);
- the pump allows water pressure to be increased until 8-
9 bars for brewing.
The electronic control unit controls the level of the water
in the boiler.
When this level drops the contact with the probe is in-
terrupted; the control unit sends an impulse to the inlet
solenoid valve and the power pump, which restore the
normal level of water in the boiler.
To avoid possible flooding due to machine malfunctions
or leaks in the water circuit, the electronic control unit is
equipped with a timing device that cuts off the automa-
tic filling after a maximum period of 120 seconds.
Attention
Always check the level of the water in the boiler by
means of the level-check window located on the
front of the machine.
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A
B
Maintenance manual for technical assistance

1.3.6.4. Flowmeter

The flowmeter measures the quantity of water sent to
the brewing unit for espresso brewing.
The flowmeter generates some electric impulses which
are sent to the electronic control unit. These impulses
are read by the control unit and memorized during the
programming of the dose.
The flashing of the led (1) indicates that the electrical
impulses have been sent from the flowmeter to the con-
trol unit.
1

1.3.6.5. Pressure switch

The pressure switch allows controlling the boiler pres-
sure by activating or bypassing the heating element in
the boiler. any calibration of the pressure switch which
may be required can be carried out with the machine in
operation by means of the screw (a) located on the com-
ponent case.
Attention
The internal contacts of the pressure switch may be
subjected to oxidation. It is recommended to clean
the contacts with anti-oxidant spray periodically.
Manual code 10066846 / Rel. 0.00 / March 2012
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