Operation
Slim Jim Idrocompresso User manual
page 13
Pressure gauge
While brewing a real shot the coffee-bed becomes less permeable during wetting (pre-infusion stage)
and pressure will rise to water mains pressure (or pressure reducer setting) while the brew-lever
remains locked. Immediately after unlocking the pressure will increase to (ideally) 9 bar after which it
will slowly decrease during the brew. The pressure gauge displays the pressure in the line that runs
from group-valve to group-screen. This means that when a group is inactive or when no portafilter is
locked in, the pressure gauge will display 0 bar.
The pressure gauge shows the actual pressure
on the coffee bed.
When the group is inactive, the pressure
displayed is thus (very close to) 0.
When 9 bar pressure is not reached at the start
of a normal brew, either the spring length is not
set correctly or the coffee bed was not able to
produce enough counter pressure. Insufficient
counter-pressure can be caused by too few
and/or too coarse coffee particles, channelling in
coffee bed during extraction, etc.
Figure 13. The brew pressure gauge.
Dispensing hot water
Push button switch for timed dispense of non-
sputtering mix-water.
Momentary toggle switch for dispense of water
directly from steam boiler.
Figure 14. The hot-water toggle switch and mix-water push button switch.
Mixed water
Press the mixed-water push button switch down briefly. The flow will stop when the pre-set time has
elapsed, or when the switch is pressed down briefly again, whichever comes first. The pre-set time
can be adjusted in the Barista-menu.
A technician can manipulate the cold inflow with a set-screw on the manifold inside the machine to
optimise the mix-water temperature.
Hot water
Press-hold the toggle switch down to start water flowing directly from the steam boiler to the spout. It
will take a moment before the water starts to sputter indicating that boiling water is being dispensed.
The duration of that moment depends on the temperature of the intermediate parts just prior to
pressing the switch. The flow will stop when the switch is released.
Note
!
Hot water can only be dispensed when the steam boiler is above 100°C as steam pressure is the
means to push the water out of the boiler. When the steam boiler is not at operational temperature yet,
the mix-water temperature will be lower than the set temperature.
