Patent ID: 7491035

Claim:
A condensate pump, comprising: a condensate reservoir comprising a fluid inlet, an inlet check valve operable to prevent a flow of fluid out of the condensate reservoir through the fluid inlet and to allow a flow of fluid into the condensate reservoir through the fluid inlet, a fluid outlet, and an outlet check valve operable to prevent a flow of fluid into the condensate reservoir through the fluid outlet and to allow a flow of fluid out of the condensate reservoir through the fluid outlet; a liquid level sensor operable to sense a liquid level within the condensate reservoir; and a pressure/vent valve further comprising a primary piston slidably supported in a primary cylinder, wherein the primary piston slides in the primary cylinder responsive to the liquid level sensor, between a first primary piston position and a second primary piston position, a pressure source, a pressure vent, a three-way valve further comprising a secondary piston slidably supported in a secondary cylinder, wherein the secondary piston slides in the secondary cylinder between a first secondary piston position in which the pressure source is in communication with a gas space of the condensate reservoir and the pressure vent is isolated from the gas space, and a second secondary piston position in which the pressure source is isolated from the gas space and the pressure vent is in communication with the gas space, and wherein the movement of the secondary piston in the secondary cylinder is responsive to movement of the primary piston in the primary cylinder.