La Marzocco GB/5 Manual page 13

When the espresso machine is ready to
operate all lights on the keypads will light.
3) Brewing after irst installation
Once the irst installation procedures are
inished, before proceeding with brewing
coffee, hot water and steam, please follow
these steps:
- Engage the portailters by inserting
them into each group, brew water through
each group 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
4) Installing the portailters
Install the portailter(s) by inserting them
into the group and rotate the handle from
left to right. When the portailters are
inserted properly, you can press any of brew
buttons to start the low of water through
the portailter. You should allow hot water
to pass through the empty portailter(s) for
a few seconds each time, in order to pre-
heat the portailter.
Note: It is important to leave the portailters
installed in the espresso machine when
not in use. The portailter must remain
heated for the brew process to function
correctly.
5) Water pump
Whenever you are brewing coffee, you can
adjust the pump pressure by turning the
by-pass screw (below the plug
located on the side to which the pump
power supply is connected) clockwise to
increase and counter-clockwise to reduce
pressure. Adjust pressure only when at
least one group is brewing coffee.
Note: When the heating element in the
coffee boiler is energized, the water will
expand increasing the start-up pressure.
Once the maximum pressure is reached,
the expansion (safety) valve should start
working by discharging a few drops of
water, in order to prevent such pressure
from exceeding 11-12 bar.
In case the pressure exceeds 12 bar,
you must adjust the expansion valve by
unscrewing the cap slightly. If this is not
suficient, 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.).
Filter Basket
Porta Filter
O-ring Gasket
Double Spout
6) Brewing coffee
It is now possible to remove one of the
portailters to make an espresso beverage.
Place some ground coffee in the ilter
itself: 1 dose (approximately 6-7 g) for
the small ilter, 2 doses (2 approximately
12-15 g) for the larger ilter. Press down
on the ground coffee with the supplied
tamper and install the ilter holder up
again to the bottom of the group and then
press a button (AV model) to begin the
brewing process, or move the paddle lever
(MP model see picture below).
off pre-brewing brewing
Note: Some baristas believe it is important
to press the brewing button prior to
installing the portailter to allow the water
to lush any remaining coffee oils and
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