This switch is engaged down to turn on and automatically springs back to the off position.
GB5/FB80 users: this switch has replaced the old square one # E.1.008 (MZ_340) on the GB5 and FB80 models after serial number 843. La Marzocco decided that the E.1.008 switches were sub-standard, and opted to go back to this standard hot water switch. An adapter is required in equipment wired for pin connections.