La Marzocco STRADA EE Operating Manual - page 6
EN
6
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 8,2 liters
3000 Watts
3 groups 11,8 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. 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,
developed mechanically by a special
positive-displacement pump which
is activated automatically every time
coffee is brewed.
• Pressure is displayed through a
pressure gauge with a scale from 0 to
15 bar.
• Safety device, based on an expansion
type
mechanical
valve,
with
counteracting spring adjusted to 13.5
bar.