Maintenance And Weekly Cleaning Operations - La Marzocco FB 70 Operating Manual

6. Maintenance and weekly cleaning operations

The machine must not be dipped in, nor splashed
with, water in order to clean it. For cleaning opera-
tions, please follow the instructions listed below very
carefully.
Cleaning groups and drain wells
- Put a tablespoon of detergent powder for coffee
machines into the blind filter, supplied with the machine,
and tighten it onto the group you want to clean by using
a normal filter holder.
- Press the brewing button for said group, as if you were
making a regular cup of coffee.
- Stop the water after about 15-20 seconds.
- Start and stop the group several times until you notice
clear water coming down, instead of soapy water, when
you remove the filter holder.
- Rinse the group using a normal filter, by running hot
water through it several times.
Caution:
Never remove the filter holder when water is being deliv-
ered. This operation can be extremely dangerous since
the high pressure built-up inside the blind filter would
spray out hot and slightly caustic water, which may
cause severe burns.
Cleaning filters and filter holders
- Put 2 or 3 teaspoons of detergent powder for coffee
machines in about 1/2 a litre of water inside a heat-resist-
ant container and boil.
- Dip filters and metallic part of portafilters in the boiled
solution and leave them fully submerged for about 30
minutes.
- Rinse thoroughly with clean water and run hot water
through one group several times with the filters in place.
- Make one cup of coffee in order to remove any
unpleasant savour.
Cleaning the drain collector
Remove the drain tray grill every night, pull out the
water drain collector and clean it thoroughly. Also
inspect and clean the drain well (part 19) at least twice a
week, and remove any leftover grounds with a table-
spoon.
Cleaning the body
Wipe the stainless steel surfaces with a soft cloth in the
direction of the glazing marks, if any. Do not use any
alcohol or solvents whatsoever on painted or imprinted
parts in order not to damage them.
Cleaning the hot water and steam nozzles
Steam nozzles must be cleaned immediately after use
with a damp cloth and by producing a short burst of
steam so as to prevent the formation of deposits inside
the nozzles themselves, which may alter the savour of
other drinks to be heated.
Cleaning the diffusion screens (infusion filter)
Due to filter holder discharge operations (subsequent to
coffee brewing), a certain amount of coffee grounds may
slowly build-up on and obstruct, even partially, the infu-
sion filter. To clean it up, you must first remove it by
unscrewing the retainer screw, then proceed to hold said
filter with a pair of pliers and burn off the wood particles
contained in the coffee grounds by using a gas stove or
the flame from a cotton ball soaked in ethyl alcohol. In
the latter case, keep well clear of the alcohol contain-
er when lighting the cotton ball and do not add any
alcohol at all while the cotton is burning.
SCREW
DIFFUSER - fig. 5
Motor Pump
It is of the positive-displacement type and can develop a
pressure of 14 bar. The operating pressure is 8-9 bar and
is preset in-factory during testing; however, such pres-
sure may vary from place to place since the pump
"absorbs" the pressure in the service water pipes to
which it must be connected. You can always check the
pressure itself by looking at the lower scale on the pres-
sure gauge (part 3, Fig. 1 or 2) whenever you are brew-
ing 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 supply 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 2)
you also give power directly to
the coffee boiler. If you acti-
vate the motor pump when the machine is cold, a start-up
pressure of 8-9 bar will develop; thus, once the heating ele-
ments 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 11 bar.
In case the pressure exceeds 11 bar, you must proceed to
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 in case the valve remains
open in the drain position (i.e. the pressure cannot increase
to 8 bar approx.).
Purifier
It is of the "ion exchange" resin type. Such resins must
be regenerated weekly with ordinary table salt, as indi-
cated on the label affixed to the purifier. An efficient puri-
fier results in the machine working properly.
Using the machine without having adequately regener-
ated the purifier (at least once a week for supply water
having a hardness of between 9 and 13 French degrees)
may cause the machine to work improperly. The manu-
facturer declines any responsibility in this case.
DIFFUSER
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