A steam trap should be installed immediately before pressure reducing valves / control valves to prevent condensate from pooling when the valve is closed. The trap also helps reduce erosion of the valve seat from condensate. Similarly, traps are also generally installed between two pressure reducing valves in a series installation to remove condensate trapped between the valves during operation or shut-off.

A steam trap should be installed in front of valves closed for long periods of time to help eliminate the pooling of condensate which could otherwise be propelled at high speed down the pipeline when the manual valve is opened. Similarly, a steam trap is needed at the end of a pipe run (end of main) to help drain the system for safe and effective operation.