If you are having trouble with vapor lock on your espresso machine, try this vacuum breaker valve. What is vapor lock? It is when you put your espresso machine on a timer so it will be ready when you get up, only to find that as soon as you open the steam valve, your pressure drops to zero in a matter of seconds and your group is not hot. You can either use it like it is or you can attach a piece of silicone tubing to the top and tap into the discharge side of your expansion valve or where ever else you would like to divert any moisture that escapes from the top prior to it seating. **NOTE**: We know this valve will not work in Pasquini or Mini Vivaldi espresso machines. There is not enough clearance between the top of the boiler and the top cover of the machine. I does however work quit nice in Rocket machines. If you want to attach tubing to the top, it's best to have at least 2" of clearance.