So you’re finally getting to researching machines, and as you do, you get a bit of an information overload. Pretty much everyone does. One of the first features that throws people off is the three-way solenoid valve, and what it means.
By definition (thanks to Wikipedia): A solenoid valve is an electromechanical valve for use with liquid or gas. The valve is controlled by an electric current through a solenoid coil. Solenoid valves may have two or more ports: in the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the outflow is switched between the two outlet ports.
So what does it do for you? It makes clean up a breeze and will extend the life of your machine. What the valve actually does is a bit more complicated. The three-ways are this: in from the pump, out through the brew group, and out into the drip tray. What happens is when you deactivate the pump, the solenoid switches, and cuts off water in from the pump, cuts the outlet from the brew group and kicks it out into your drip tray. Thus instantly relieving the pressure from the brew group, and creating a dry ‘puck’ as opposed to a kind of ‘mud’. The solenoid is also how prosumer machines backflush(the process of blocking water at the brew head creating a pressure build up between the pump and group head, cleaning out any residue built up in the line), but we do NOT recommend backflushing for any small machines, solenoid valve or not. They just aren’t built for the rigors or backflushing. Use Urnex Cleancaf to keep the smaller machines free of scale. One wrong backflush on a smaller machine, and your machine will need a trip to our top rated service department.
So if you want an easy cleanup, with the benefit of a longer machine life, I highly recommend making sure you have a three way solenoid valve. Machines like the New Baby, the Rancilio Silvia, and any Prosumer machine have them.