4.4 Automatic Water Entry
The Automatic Water Entry system is for checking the
boiler level. It is composed of:
• level probe (short) (1) and safety probe (long) (2) in-
serted in the boiler, composed of a stainless steel rod;
• electronic control unit (3);
• hydraulic circuit controlled by a
motor pump and solenoid valve
controlled by the electronic
control unit.
When, during the normal
operation of the machine, the water
level drops down, the level probe
(1) sends a signal to the electronic
control unit (3), which activates the
motor pump and the lling solenoid valve, thus restoring
the level of water in the boiler.
If the level is very low or there is no water in the boiler
(during the machine's installation or due to a failure),
the safety probe (2) sends a signal to the control unit
which deactivates the heating element to keep it from
overheating and activates the motor pump and the
solenoid valve to restore the level of water in the boiler.
To avoid possible flooding due to machine
malfunctions or leaks in the hydraulic circuit, the
electronic control unit includes a timing device that cuts
o automatic lling after a maximum operating time
(roughly 30 seconds). During the installation of machines
with three or four groups the initial water lling time
may exceed the established time limit. In this event,
just switch the machine o and then back on to restore
normal operating conditions.
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2
4.5 Volumetric dosing
The volumetric dosing device serves the purpose of
measuring the quantity of water sent to the group of
espresso delivery.
The dosing device generates an electrical impulse
which is sent to the electronic
control unit.
This impulse is read by the
control unit and memorized
during the programming of
the dose.
The ashing of the LED (1)
indicates that the electrical
impulse has been sent from
the dosing device to the control unit.
4.6 Pressure switch
The machine includes two types of pressure switches:
COFFEE BOILER PRESSURE SWITCH
Each coffee boiler is equipped with a
pressure switch to control the pressure.
Calibration is set to 2 bar and can be
distinguished by the green seal.
SERVICES BOILER PRESSURE SWITCH
The services boiler is provided with a
pressure safety switch which prevents exceeding the
calibration value.
Calibration is set to 1.5 bar and can be distinguished
by the RED seal.
4.7 Anti-ooding device
The cover installed on the pressure relief valve makes
it possible to collect any water which may leak from the
boiler due to malfunction and channel it to the drain
pad, by means of a
special hose.
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