How a Silvia Works
All wiring
Off
On, heating up
On, at temp
Brewing espresso
Steam, heating up
Steam, at temp
Pumping hot water
Overheated
Modification for PID
Dual Setpoint PID
Advanced Dual Setpoint PID

Coffee Cup
HOME
Power on, Boiler is Heating up to Brew Temperature

The power switch is in the on. You can see that the contacts in the power switch are closed and electricity flows through the switch, first through the brew thermostat and then through the steam thermostat to get to the heating element. Even though you are not using the steam function at this time, electricity still flows through both thermostats.