Astoria 2GR - Page 17

TECHNICIANS' manual
19 of 108
2.9.7 LEVER group
The group lever uses the heating unit pressure and water. This
system does not require heat exchangers.
When the lever (1) is lowered, the spring (2) inside the group
is compressed: the piston (3) raises, allowing the water to en-
ter the pre-infusion jacket.
When the lever is released, the piston compresses the water
at 8-10 bar, allowing the espresso coffee to be dispensed.
The check ball valve (4)preventsthewaterfromowingback
into the heating unit (5).
1
45
2
3
PHASE 1
Lowering the
lever
PHASE 2
Pre-infusion for
3-5 seconds
PHASE 3
The lever releases
and coee is dis-
pensed.
2.9.8 Group with an EXTRACTABLE
exchanger
The dispensing group heating is provided by direct contact
with the heating unit. The water used to dispense coffee is
taken from a so-called "extractable" exchanger which is im-
mersed in the heating unit’s water:
• When the solenoid valve and pump activate, this allows
cold water to enter into the exchanger (1).
• The heating unit water is carried from the exchanger (1)
to the group (2) for dispensing.
• Thepumpallowsthewaterowpressure to increase to
0.8-0.9 MPa (8-9 bar).
The version of the extractable exchanger for the Italian mar-
ket does not include the suction hose (3) and seal (4).
If necessary, the exchanger can be replaced without having
toremovetheange:loosenthescrews,removethedispens-
ing group from the heating unit and remove the exchanger.
These operations should be carried out when the machine
has been switched off and has cooled down: always replace
the seals.
4
2
1
2
Water
inlet
Dispensing
coee