Selecting the proper steam trap is important in effective operation of steam systems. Steam traps are automatic valves that open to pass condensate and close to prevent the flow of steam. The functions of a steam trap in a steam system are to: - Vent air from the system so steam can enter - Hold steam in the system until the steam latent heat is removed - Drain condensate from the system as it is formed after the latent heat is removed. Removing condensate from piping helps prevent erosion and water hammer. Removing condensate from heat exchangers is required to make room for new steam for the heating process.