La Marzocco kb90 Series, Manual

Page: 8 / 144

EN
8
1) General Description
The machine is built in 2 and 3 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 7,0 liters 3000 Watts
3 groups 11 liters 4000 Watts
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 temperature probe and PID controller.
The steam boiler has various fittings used
for safety devices, for supplying hot water
and steam, and for the heating element.
Composed of AISI 300 series stainless
steel tube. Heating is accomplished
through an immersion-type plated heating
element.
• Operating pressure of 1.3-1.5 bar,
controlled automatically through a
pressure switch or a temperature
probe, adjusted to open the heating
element supply circuit at 1.5 bar and
close it at 1.3 bar.
• The pressure is displayed by means of
a pressure gauge with a scale of 0 to 2
bar.
• Safety device, based on an expansion
type mechanical valve, with counter-
acting spring adjusted to 1.8 bar.
• Testing: hydraulic test at 4.5 bar
performed on ready-to-use small
boilers, at our factory.
• Coffee Boiler
The Coffee Boiler consists of a cylindrical
tank made of AISI 300 series stainless
steel. One each group (hot water generator
for brewing coffee).
Each unit is subject to a hydraulic test,
at a pressure of 18 bar, and has an
operating pressure of 9 bar. The following
is a list of effective volume and power
ratings according to the number of groups
installed:
2 groups 2 x 1,3 liters 2 x 800 Watts
3 groups 3 x 1,3 liters 3 x 800 Watts
Covers are installed at either end of the
cylindrical tank and on one of them there
is 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.
Composed of an AISI 300 series stainless
steel tube. Heating is accomplished
through an immersion-type plated heating
element.
• Operating temperature 95°C
(adjustable), controlled automatically
by an electronic temperature controller
with an accuracy of 0.2 °C. Operating
pressure of 9 bar.
• Pressure is displayed through a pressure
gauge with a scale from 0 to 18 bar.
• Safety device, based on an expansion
type mechanical valve, with
ounteracting spring adjusted to 13 bar.
• Testing: Hydraulic test at 18 bar
performed on ready-to-use small boilers,
at our factory.