La Marzocco Linea PB Manual - page 6
EN
5
1) General description
The machine is built in 2, 3, and 4
coffee group versions and is essentially
composed of the following parts:
• Steam Boiler (produces steam and hot
water);
• Coffee (“saturated”) 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 hydraulic 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 liters
3 groups
11 liters
4 groups
15 liters
Covers are welded 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 is maintained by an electronic
temperature probe with a PID controller.
The steam boiler has various fittings used
for safety devices, for supplying hot water
and 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
3 groups
5 liters
4 groups
6.8 liters
Covers are welded 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. The brewing group
accepts the portafilter used to hold the
ground coffee; the espresso flows through
the brewing group, through the portafilter
basket, through the portafilter spout, and
into the cup(s) after the brewing button
has been pressed.
• Exterior cover
The exterior consists of painted
and stainless sheet steel panels. To
provide good aesthetics, to optimize
ergonometrics for the operator and
to reduce the chance of damage to a
minimum.
• Water pump
The rotary vane pump, is installed on
the water supply tubing and is set up to
operate anytime the coffee groups are
activated, and through an autofill system
whenever the water boiler needs to be
replenished.
• Sound pressure
The weighted sound pressure level of the
machine is lower than 70dBA.
• Water inspection window
The position of this device enables to
verify only water presence inside the
steam boiler. The water level in the
window provides a reference about
the water level in the steam boiler,
but doesn’t represent it in a directly
proportional way, 1/3 of the windows is
equal to approximately 1/2 of the boiler.