La Marzocco GB/5 Manual page 6

1) General description
The machine is built in 2, 3, and 4 group
versions and is essentially composed of
the following parts:
• Steam Boiler (produces steam and hot
water)
• Coffee ("saturation") boiler
• Brewing groups
• Exterior Cover
• Water pump
2) Description of the various parts
• Steam Boiler
The Steam Boiler consists of a cylindrical
tank, of varying length according to the
number of coffee groups, which is made
of AISI 300 series stainless steel. Each
unit is subjected to a bench test, at a
pressure of 6 bar, and has an operating
pressure of 1.3-1.5 bar. The following
is a list of effective volumes and power
ratings according to the number of groups
installed:
2 groups 7.0 liters 2000 or 3000 Watts
3 groups 11 liters 3000 or 4000 Watts
4 groups 15 liters 3800 or 5000 Watts
Covers are installed at either end of the
cylindrical tank and on one of them there
is a housing for the water-heating element,
which allows the steam boiler to reach
operating pressure within approximately
25 minutes. Operating pressure
maintained by a pressure switch or a
5
temperature probe. The steam boiler has
various ittings used for safety devices, hot
water, steam, and for the heating element.
• Coffee boiler
The Coffee Boiler consists of a cylindrical
tank, of varying length according to the
number of coffee groups, which is made
of AISI 300 series stainless steel. Each
unit is subjected to a hydraulic test, at a
pressure of 18 bar, and has an operating
pressure of 9 bar. The following, table
is a list of effective volumes and power
ratings according to the number of groups
installed:
2 groups 3.4 liters 1400 Watts
3 groups 5.0 liters 1600 or
1900 Watts
4 groups 3.4+3.4 liters 1400+1400 Watts
(2 Boilers Installed)
Covers are installed at either end of the
cylindrical tank and on one of them there is
a housing for the water heating elements.
The temperature of the coffee boiler is
maintained by an electronic temperature
controller (PID capable) with an accuracy
of 0.2°C. The brewing groups are installed
on the boiler.
• Brewing groups
They consist of a precision casting
made of stainless steel.
is group accepts the portailter used to
hold the ground coffee; Hot water under
pressure lows through the brewing group,
through the portailter basket, through
the portailter spout, and into the cup(s)
after the brew button has been pressed
preparing espresso.
• Exterior cover
It consists of a stainless sheet steel
body for the GB/5 and painted plastic
for FB/80. The structure has been the
object of speciic studies to provide good
aesthetics, to lower ergonometric costs for
the operator and to reduce the chance of
damage to a minimum.
• Water pump
The water pump, is a differential pressure,
"positive-displacement"
on the water supply tubing and is set-up
to operate anytime the coffee groups are
activated, and through an autoill system
whenever the steam boiler needs to be
replenished.
• Sound pressure
The weighted sound pressure level o f the
machine is lower than 70dBA.
WARNING
THE MACHINE IS INTENDED TO BE PERMANENTLY
CONNECTED TO FIXED WIRING, AND IT IS MANDATORY
The brewing
THAT A RESIDUAL CURRENT DEVICE (RCD) WITH
A RATED RESIDUAL OPERATING CURRENT NOT
EXCEEDING 30 mA IS INSTALLED.
type installed