USER MANUAL - operation
Slim Jim User manual
page 8
Pressure gauge
While brewing a real shot the coffee-bed becomes less permeable during wetting (pre-infusion stage)
and pressure will rise until pump-pressure is reached (ideally 9 bar). The pressure gauges display 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.
Figure 8. The brew pressure gauge.
If 9 bar pressure is not reached during a normal brew, either the pump pressure is set too low 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 grinds, channelling in coffee bed during extraction, etc.
Dispensing hot water
Momentary toggle switch for dispense of water
directly from steam boiler.
Push button switch for timed dispense of non-
sputtering mix-water.
Figure 9. 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.
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.
