📹 How It Works: Steam and Hot Water Valves Updated February 09, 2022 17:37 Learn how espresso machine steam and hot water valves work. Includes information on no-burn steam wands, as well as single boiler style valves. How It Works: Espresso Machine Steam & Hot Water Valves Steam & Hot Water Valves (00:00) No-Burn Steam Wands (06:28) Single Boiler Style Valve (08:54)