La San Marco 20/20 CLASSIC Serie Emploi Et Entretien page 48

DEFECT
4. The machine was started
properly but one or more
brewing group boilers
does not warm up.
5.
brewing group.
6. The programmed espresso
coffee doses are not
constant or vary across the
different brewing groups.
7. It is not possible to
programme the dose
quantities on group 1 and
copy them to the other
groups.
8. Flow meter alarm.
CAUSE
brewing group is defective or
not connected.
OFF.
or there is too much coffee for
the type of filter used.
group doesn't open because
it's faulty.
electronic control unit or flow
meters.
electronic control unit or flow
meters.
not working.
defective.
SOLUTION
position 2.
groups are set to OFF.
must check the electrical wires
powering the heating element.
Moreover, it is important to check
whether the thermostat tripped the
heating element safety and to check
its correct operation.
coffee ground.
in the "open" position.
must check the flow meters and their
valves.
must check the brewing group
solenoid, its wiring and the fuse in
the electronic control unit.
must inspect and check that the
water circuit is not obstructed or
whether a pump fault is possible.
each of the brewing groups.
must check, and if necessary
replace, the group's flow meter.
Check and if necessary replace the
group's solenoid. Check the water
nozzles.
must check the electrical wiring
between the control unit and the
flow meters and replace them if
necessary.
must check the electrical wiring
between the control unit and the
flow meters and replace them if
necessary.
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