La Marzocco linea Manual De Instrucciones página 20

remove it by unscrewing the retainer
screw, then soak in espresso detergent
powder.
DIFFuSER SCREEN /
SCREW
INFuSION FILTER
DIFFuSER - fig. 5
Motor Pump
The motor pump is of the positive-
displacement type and can develop a
pressure of 14 bar. The operating pres-
sure is 8-9 bar and is factory preset during
testing; however, such pressure may vary
from place to place since the pump pres-
sure is affected by the incoming water
mains pressure. You must always check
the pressure itself by looking at the lower
scale on the pressure gauge (part 3, fig.
1 or 3; part 4, fig. 2) whenever you are
brewing coffee, and you can increase
such pressure, as required, by turning the
by-pass screw (below the plug located on
the side to which the pump power sup-
19
ply is connected) clockwise, or reduce it
by turning the screw counter-clockwise.
Adjust pressure only when at least one
group is brewing coffee.
IMPORTANT
When you activate the motor pump by
pressing the specific button (part 8, fig.
1 or 3) you also give pressure directly
to the coffee boiler.
If you activate the
motor pump when
the machine is cold,
a start-up pressure of
8-9 bar will develop;
thus, once the heat-
ing elements start working and the water
temperature increases, the liquid will
expand increasing the start-up pressure
by about 3 bar, for a total pressure of 11
bar. Once operating pressure is reached,
the expansion (safety) valve (part 19A)
should start working by discharging a few
drops of water, in order to prevent such
pressure from exceeding 12 bar.
If the pressure exceeds 12 bar, you must
adjust the valve by unscrewing the cap
slightly. If this is not sufficient, remove
the valve and clear away any calcium
deposits. This remedy is valid also if the
valve remains open in the drain position
(i.e. the pressure cannot increase to 8 bar
approx.).
If the machine has not been used for
more than 8 hours or, in any case, after
long periods of being idle, in order to use
the machine to its full potential it is nec-
essary to perform some cleaning cycles
before brewing beverages as follows:
- Groups: with the portafilters engaged
in the groups brew water through each for
at least two minutes
- Being careful to avoid burns, turn on
each steam wand for at least one minute.
- Turn on the hot water valve for the
time necessary to allow the following
quantities of water to be brewed:
At least 1 liter for a 1/2 group machine
At least 2 liters for a 3 group machine
At least 3 liters for a 4 group machine
If the machine is not going to be used
for long periods of time, it is advisable to
follow these safety indications:
- Disconnect the machine from the
water mains or interrupt the water con-
nection via a mains tap.
- Disconnect the machine from the elec-
trical mains.
WARNING
IF THE ABOVE-MENTIONED INSTRUCTIONS
ARE NOT ADHERED TO THE MANUFACTURER
CANNOT BE HELD RESPONSIBLE FOR
DAMAGE TO PERSONS OR THINGS.