Steam traps are selected to automatically discharge condensate and non-condensable gases from steam systems while preventing live steam loss. Incorrect trap selection leads to waterlogging, reduced heat transfer efficiency, water hammer, and excessive energy consumption — making trap type, differential pressure rating, and condensate load the primary selection criteria.

Ball float steam traps provide continuous, modulating condensate discharge proportional to condensate flow rate, making them the preferred choice for applications with high or variable condensate loads such as heat exchangers, process heaters, and steam jacketed equipment. The float mechanism responds immediately to condensate level changes, ensuring consistent drainage without the cyclic discharge pattern of thermostatic or thermodynamic traps. Thermodynamic disc steam traps are selected for high-pressure steam mains and tracer lines where compact size and simple construction are required, operating on the pressure differential between flash steam and condensate. Thermostatic bellows traps discharge condensate only when it has cooled below steam temperature, making them suitable for tracing applications and small process lines where subcooled condensate discharge is acceptable.

Steam trap selection is determined by operating pressure, differential pressure across the trap, condensate load, and required discharge pattern. Ball float traps are standard for continuous duty at low-to-medium pressure (PN10–PN40), thermodynamic traps for high-pressure steam mains up to PN400, and thermostatic traps for low-pressure utility and tracing service. Body material selection — carbon steel (WCB) for standard steam service, stainless steel (SS316) for clean steam and corrosive condensate — is based on fluid quality and system cleanliness requirements.