La Marzocco GS/3 Owner's Manual page 25

Steam Boiler
Pressure Gauge
When brewing, the coffee boiler
pressure should be between 8-10
bar. The steam boiler pressure should
be set at 2 bar but can operate at any
setting between 1.3 bar and 2 bar.
When the espresso machine is
12
ready, place ground coffee into the
portafilter and activate the brewing
process. For additional information
to operate this espresso machine
please refer the the Owner's Manual
or the Software Programming Guide.
Coffee Boiler
Pressure Gauge
25