Expansion Valve Release Adjustment - La Spaziale S1 Vivaldi II Owner's Manual

8.4 Expansion Valve Release Adjustment

This procedure starts by removing the chrome front panel as in the above procedure
and also requires the portafilter with rubber disk or blind filter basket.
1. Adjust the group pressure to 12.5 bar per the following instructions:
a) Loosen lock nut "A" using the 14mm wrench
b) Tighten nut "B" 1-2 turns using the 10mm wrench
c) Turn on pump until pressure on the Group Pressure gauge "D" stabilizes
d) Repeat steps b & c until pressure reads 12.5 bar
2. The expansion valve "C" should open at 12.5 bar
3. If no water is dripping or running from the tube below nut "C" at 12.5 bar the
expansion valve is set too high. Use the 21mm socket to loosen nut "C" (rotate
counter-clockwise as viewed from the bottom of this valve) until the valve just opens
when running the pump as the pressure reaches 12.5 bar.
4. If water is pouring out of tube below "C" before the pressure hits 12.5 bar, use the
21mm socket to tighten nut "C" (rotate clockwise and viewed from the bottom of this
valve) until the valve is just opening at this pressure. If you back off the PF pressure
to 12 bar all dripping should stop - though it may take a minute or two for residual
moisture to drip out.
5. Once you are convinced that the expansion valve is properly calibrated, readjust the
rotary pump pressure by unscrewing "B" to reach your preferred pressure - normally
in the range of 8.2 to 9.0 bar. Then tighten lock nut "A".
Notes:
1) Make small adjustments, then turn the pump on and check. Don't attempt any
of these adjustments while the pump is on.
2) The term expansion valve is somewhat of a misnomer as this device is really the
overpressure valve for the group boiler. The steam boiler has its own dedicated valve.
S1 Vivaldi II Owner's Manual
Page 24