Abstract: A steam trap includes a replaceable condensate nozzle cartridge with a through passage forming a venturi nozzle in a straight-line working fluid flow path. The venturi through passage includes a venturi nozzle insert that reduces the pressure of the working fluid to cause the liquid water in the working fluid to flash and restrict the flow of steam through the passage. The condensate nozzle is located in a reduced pressure discharge chamber into which a nozzle outlet discharges water condensate extracted by the nozzle and emptied from a trap outlet. The reduced pressure discharge chamber has an access opening sealed by a removable cover to allow the nozzle cartridge to be removed and replaced if necessary, without removing the steam trap from the process line. Locating the removable nozzle cartridge in a lower pressure region of the steam trap overcomes rating limitations on prior steam traps with replaceable venturi nozzles.