S1 Owner’s Manual
Page 17
7.3 Group Pressure Test and Adjustment
This adjustment and the one covered in the next section require a portafilter pressure
gauge such as the one pictured below which comes mounted on a dedicated portafilter.
Your S1 dealer should be able to sell you this one or you can get generic gauges which
screw onto your own portafilter spout.
Removal of the chrome panel behind the portafilter is required. This is the panel
through which protrudes the boiler pressure gauge. Use a large Phillips screwdriver to
remove the two screws adjacent to the numbers (5) on the diagram on page 2. Then
remove the panel. Attach the pressure gauge to the portafilter. The adjustment screws
are located just above the letter “E” in the diagram below. First, loosen the lock nut
(14mm wrench). Press the One Cup (24) or Two Cup (25) button and wait for the
gauge pressure to stabilize. Most users prefer group pressure in the range 8.2-9.0 bar.
Turning the adjuster nut (10mm wrench) counter-clockwise lowers the pressure, turning
it clockwise increases the pressure. When it is set to your preferred pressure, tighten
the lock nut and recheck. Then reattach the front panel. Should your water supply
pressure change significantly, readjustment will be required as the rotary pump supplies
an adjustable boost to the supply pressure. However, if you add an in-line pressure
regulator to the water supply line this should not be required. If your water supply
pressure is higher than 30psi, a water pressure regulator can also reduce or eliminate
expansion valve drips.
7.4 Expansion Valve Release Adjustment
This procedure starts by removing the chrome front panel as in the above procedure
and also requires the portafilter pressure gauge.
