A vapor blast system includes a pressure pot with an upper end and a main body, a fill inlet attached to the upper end of the pressure pot, and a seal assembly disposed in the pressure pot. The seal assembly is configured to control a flow of a fluid between the pressure pot and the fill inlet. The seal assembly includes a pop-up seal, a pipe, and a spring. The pop-up seal comprises an upper surface, a lower surface disposed opposite the upper surface, a blind hole disposed in the upper surface, a bore disposed in the lower surface, and a centerline axis disposed through a center of the pop-up seal. The pipe is attached to a lower surface of the pop-up seal, wherein a portion of the pipe is received by the bore. The spring is disposed in the bore and engaged with the pipe.