A pump includes a pump body defining a fluid chamber and inlet and outlet ports in fluid communication with the fluid chamber, an inlet check valve connected to the inlet port, an outlet check valve connected to the outlet port, and a piston housing coupled to the pump body and defining a piston chamber. A piston assembly is disposed at least partially within the piston chamber and at least partially within the fluid chamber and includes a piston and a poppet connected to the piston in proximity to the pump body. In addition, the pump includes a gland disposed between a portion of the piston housing and the pump body. Further, the pump includes the poppet having a poppet head axially connected to a diaphragm coupled to a poppet flange. The poppet head is connected to the piston.