Fuel cell system hot zone pressure regulator

A method of using a pressure regulator (134) in a fuel cell system (10) is disclosed. The method comprises controlling a purge gas pressure (P1) of a purge gas (116) disposed in an enclosure (102) disposed around a fuel cell stack (124) and a waste energy recovery assembly (126), by seating a pressure plunger (144) in a seating portion (146) of a pressure regulator (134), wherein the purge gas (116) unseats the pressure plunger (144) when the purge gas pressure (P1) exceeds a desired pressure (Pd). The method further comprises passing a sufficient amount of the purge gas (116) past the seating portion (146) to reduce the purge gas pressure (P1) to at least the desired pressure (Pd). A fuel cell system (10) having a pressure regulator (134) is also disclosed. The fuel cell system (10) comprises an enclosure (102). A waste energy recovery assembly (126), a fuel cell stack (124) and a pressure regulator (134) are disposed in the enclosure (102). The fuel cell stack (10) being in fluid communication with the waste energy recovery assembly (126). A purge gas (116) is in fluid communication with the enclosure (102). The pressure regulator (134) is in fluid communication with the purge gas (116) and an area external to the enclosure via the waste energy recovery assembly (126).