220V 50/60Hz 8W 1/8 F x 1/8 F Two Way ODE Solenoid Valve - Ideal for Water Control in Industrial Automation and Irrigation Systems

These will work in any machine, of course, but for La Marzocco auto-fill applications they are installed backwards, with the water flowing opposite of the indicating arrow on the bottom of the brass valve body. This is not required when using this valve for the hot water dispense function.

La Marzocco states (referring to the use of the three-way valves that they use):

"The steam boiler solenoid valve is a three-way solenoid valve with one port (top port) sealed shut. The sealed top port creates a modified two-way valve. Under normal conditions the steam boiler solenoid valve operates at a constant differential pressure of 105 p.s.i. If mounted incorrectly, a differential pressure greater than 130 p.s.i could cause the solenoid valve to open thus causing the steam boiler to overfill. The overfilling of the steam boiler would render the steam boiler useless and could present a hazardous situation. This valve is orientated and installed in the machines as indicated in the drawings below (three-way version pictured) to avoid an overfill situation in the steam boiler. Any other orientation or installation of this valve is not recommended."

These employ what is called a "mechanical" seal for the valve guide, so no o-ring is used.