Adjustment Of Pump Serving Pressure; Calibration Of Steam Pressure In Boiler; Automatic Operation - Programming The Coffee Brewing Cycles - La San Marco Duale Class Bedienungs- Und Wartungsanleitung

2) Hold down a steam delivery lever 5 to allow air to escape from the system as the macchine heats up.
Release the lever as soon as steam escapes from the delivery pipe. Boiler pressure is indicated on the
0÷3 bar scale on the pressure gauge 14 (suggested value: 0.9÷1.2 bar).

5.3 Adjustment of pump serving pressure

a. Once the boiler is filled, turn the main switch to position 2 (the heating elements start to heat the water).
b. Press the continuous-feeding push button 18 for the manual serving machines or the push button 10 for
the electronic machines with automatic serving, so that the water flows out of the unit the corresponding
to the pressed button.
c. Read the water pressure value on the pressure gauge 38. The
optimum pressure is 9 bar. The pressure is adjusted to the
desired value by operating on the pump screw: the pressure
is increased by turning clockwise; it is decreased by turning
clockwise. As shown in the figure, there three different cases
for adjusting this screw, depending on the pump installed on
the machine:
- adjust only the screw
- adjust the screw and lock it with the lock nut
- unscrew the cap nut an adjust the screw.

5.4 Calibration of steam pressure in boiler

a After having filled the boiler to the proper level, turn the main switch to position 2 (the heating elements will
start to heat the water).
b Open the lever-controlled steam valve 5 to vent the air during the heating phase. Close the valve as soon
as the steam phase is reached. The steam pressure in the boiler can be read on the upper scale of the
pressure gauge 18 from 0 to 3 bar. The pressure rises to the calibration value of the pressure switch 27
in the range from 0.9 to 1.1 bar. To vary the steam pressure, turn the screw 28 on the pressure switch 27.
The pressure is decreased by turning the screw clockwise and it is increased by turning the screw counter
clockwise. The screw is adjusted by means of a screwdriver inserted into the hole on the lid of the pressure
switch. The pressure switch can be reached from the upper tray and grill.

5.5 Automatic operation - programming the coffee brewing cycles

a. Entering the programming mode
Set the main switch 1 on the machine to position "zero" (machine switched off).
Hold down the fifth button e on the first brewing unit. Now , rotate the main switch 1 to position 1 (machine
switched on). After a few seconds, release the button e. The indicator led for the button will now begin to
flash, as will the same led on all the other brewing units. The machine is now ready for programming.
b. Programming
To program the four portions on brewing unit I, proceed as follows: place the single-portion filter into the
single-portion filter holder. Use the coffee dispenser to dispense a single portion of coffee into the filter.
Mount the filter holder onto brewing unit I.
Place an espresso cup under the spout on the filter holder.
Press the first button a whose portion is to be programmed. When the coffee in the cup reaches the de-
sired level, press the fifth button e to stop brewing.
follow the same procedure to program the other portions on each group. Once the four portions on brew-
ing unit I have been programmed as desired, the relative data can be transferred to the other brewing units
by pressing the fifth button e on each unit. When each button e is pressed, the indicator led for the button
will stop flashing and remain steadily lit. This shows that the data on brewing unit I has been transferred
successfully.
c. Exiting from the programming mode
After you have finished programming the machine, press the button e (with flashing led) on brewing unit I
and all the leds will turn off. The programmed quantity of coffee will now be delivered when an automatic
brewing button is pressed.
28
PUMP sCREW