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TECHNICIANS manual
ENGLISH
2.6.8 Pressure switch
The machine includes two types of pressure switches:
COFFEE BOILER PRESSURE SWITCH
Each coffee boiler is equipped with a pres-
sure switch to control the pressure.
The calibration is fixed at 2 bars.
SERVICES BOILER PRESSURE SWITCH
The services boiler is provided with a
pressure safety switch which prevents exceeding the
calibration value.
The calibration is fixed at 1.5 bars.
2.6.9 Overflow device
The cover installed
on the pressure relief
valve makes it possible
to collect any water and
steam which may leak
from the boiler due to
malfunction and chan-
nel it to the drain pad,
by means of a special
hose.
2.6.10 Pressure relief safety valve
The pressure relief safety valve has a
calibration of 1.9 bar in order to ensure
that the pressure in the boiler services does
not exceed the value of 2.1 bar. In case of
malfunction, the valve can eliminate all the
excess pressure from the boiler.
The safety valve should be checked regularly as indicated in
Chapter"10.3 Maintenance" on page 48 ".
On all machines with 4 groups, two safety valves are installed.
2.6.11 Expansion - non-return valve
This is a valve consisting of an expansion valve and
a non-return valve.
•
expansion valve
(
A
):
the cold water sent from the pump to the coffee boil-
ers is heated. This heating causes an increase in the
volume of water. To limit pressure
increases in the hydraulic circuit,
the valve limits the maximum in-
ternal pressure of the circuit to 12
Bar.
•
non-return valve
( (
B
):
its function is that of preventing
the backflow of water from the cof-
fee boilers in the hydraulic circuit.
2.6.12 Safety thermostat
The thermostat allows to avoid damage to the heat-
ing element in case of lack of water in the boiler. The
thermostat bulb (
3
) is located inside a sheath (
1
) placed
at the center of resistance. The contacts of the thermo-
stat (
4
) are connected to the heating element (
2
). If the
heating element is exposed due to failure to load water
to the boiler, the temperature of the resistance increases
dramatically. At this point, the thermostat interrupts the
power supply to the resistance thus preventing damage.
2
4
5
3
1
To reset the thermostat, press the center button (5). However,
before trying to operate the machine, verify the causes of the
blockade of the water feeding the boiler.
A
B
