Abstract: A steam trap assembly is formed with a casing defining a valve chamber therein with an inlet for introducing fluid generally consisting of condensate and steam into said chamber and with an outlet for discharging condensate from the chamber. A bucket-type float freely movable within the valve chamber is formed with an outer surface portion adapted to engage and disengage a valve seat defining the orifice of an outlet passage through which condensate is discharged from said steam trap. The float is structured as a hollow shell member defining a downwardly directed opening and with a generally continuous body having a substantially spherical configuration extending to a mouthpiece member which is fitted in the opening of the spherical shell member to define the opening with a generally circular configuration. The mouthpiece member has a weight characteristic tending to bias the center of gravity of the float member downwardly toward the opening.