20
EN
Once the coffee has been completely
brewed, pressure in the filter holder
is automatically discharged and the
portafilter can then be removed to repeat
the operation as needed.
GENERAL NOTIONS FOR PREPARING COFFEE
Once the machine has reached both of
its operating pressure (1.2 to 1.5 bar) -
which can be checked by looking at the
upper scale in the pressure gauge - and
its operating temperature, with the body/
group already at infusion temperature,
filter holder and filter must be heated
even more since they are at the lowest
position of the group itself, and they are
partially isolated from the same due to the
rubber gasket between them.
This operation can be carried out by
activating the switches and keeping them
in the brewing position for approx. 45
seconds, after which you must turn them
off and wait for 2-3 more minutes.
During this time, the pointer of the lower
scale of the pressure gauge may reach as
high as 11-12 bar; this may occur any
time that, while activating the groups,
the motor pump forces cold water into
the coffee boiler at a pressure of 8-9
bar and, simultaneously, the software
regulating the temperature of the boiler
itself switches on heating elements in
order to bring the water contained in such
boiler up to operating temperature.
However, in this case it will be necessary
to adjust the expansion valve in such a
way that pressure never exceeds the value
of 12 bar.
Both the size of coffee granules and the
type of coffee mix used are extremely
important for being able to prepare a good
cup of coffee.
The ideal grind can be determined by
making various coffees and putting the
amount of ground coffee that you would
normally use for each cup (we recommend
at least 7 g): the best grind will be the
one allowing coffee to flow out from filter
holder spouts neither too slowly nor too
quickly.
IMPORTANT
Water temperature in the coffee boiler
and therefore in the groups can be
raised or decreased by means of software
programming, if necessary
- see next
chapter for further details.
The final adjustment of the same should
be made during tuning-up, once the
appliance has been permanently
installed. The pressure of the water on
the coffee during the brewing is very
important: for this reason it is important
to set the by-pass on the pump at 9 bar.
This value changes if there are variations
on the incoming pressure from your local
water system: should that be the case,
make all necessary technical adjustments
on the system in order to eliminate such
variations.
