Piston Assembly for an Unloader Valve of an Air Compressor

A piston assembly for an unloader valve of an air compressor includes an unloader piston having an end portion with a first bore of a first bore diameter, an intermediate portion with a second bore of a second bore diameter and an opposite end portion with a third bore of a third bore diameter; a coil spring having a central opening, one end portion disposed in the second bore of the unloader piston and an opposite end portion extending into the first bore of the unloader piston; and a balance piston including a head portion having a diameter to be disposed in the first bore of the unloader piston, and a stem portion extending from the head portion into the central opening of the coil spring and having a diameter smaller than the diameter of the head portion. The diameter of the stem portion at an end portion facing away from the head portion substantially corresponds to an inner diameter of the central opening of the coil spring. The balance piston includes a heat protection element.