9.
CHECKING BOILER TEMPERATURE/PRESSURE
Version EMA - EPU :
The pressure switch (1) makes it possible to control boiler pressure by
activating or bypassing the heating element in the boiler.
Version EVD :
The temperature (and as a result the pressure) in the boiler is controlled by a
special NTC sensor located on the boiler (2).
This sensor constantly sends information to the electronic control unit, which in
turn activates or deactivates the heating element by means of a power triac.
10. VOLUMETRIC DOSING DEVICE
The volumetric dosing device installed on the EVD electronic machines serves
the purpose of measuring the quantity of water sent to the espresso delivery
group.
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 flashing of the LED (1) indicates that the electrical impulse has been sent
from the dosing device to the control unit.
11. PUMPING SYSTEM
This is a component that feeds the machine, raising the water pressure to
8-9 bar for delivery of the coffee and automatic filling of the boiler.
Based on if the machine is equipped with an internal tank or connected to
the water mains, this varies:
•
Motor pump (1), in the versions connected to the water mains;
•
Vibration pump (2), in the versions with internal tanks.
espresso coffee machine - technician instructions
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