A condensate trap assembly 12 includes a valve body 28 accommodating a condensate trap element 34 and a valve element 36. The valve element 36 is movable by a positioner 26 to direct flow in a condensate line 10 either through the condensate trap afforded by the trap element, or through the valve bypassing the condensate trap, or to shut off the condensate line 10. The positioner rotates the valve element 36 under the control of control means 54 which responds to signals from a sensor 24 detecting the presence or absence of condensate in a monitoring chamber 16 and the temperature within the chamber 16. The control means 54 is also responsive to the temperature sensed by a temperature sensor 22 upstream of a process 2 utilizing steam or other fluid which is applied to the condensate trap assembly 12.