Hot water circulation apparatus with adjustable venturi

Abstract

A dual mode water circulation apparatus for installation in a water supply line in a building upstream of a water heater provides continuously heated water at one or more remote hot water faucets. The apparatus is connected in a water return loop that includes a portion of the water supply line that is downstream of the apparatus, the water heater, the common hot water pipe, and a return line from a remote faucet. The apparatus includes a housing having a first inlet for connection to the water return line, an outlet for connection to that portion of the water supply line that connects to the water heater, and a second inlet for connection to the water supply line. There is a chamber in the housing with the inlets and outlet connecting to the chamber. There is a check valve between the first inlet and the chamber preventing flow from the apparatus outwardly from the first inlet. A venturi is positioned in the chamber to provide reduced pressure adjacent the first inlet to cause an increase in flow in the water return loop when water flows into the apparatus from the water supply pipe. There is a variable capacity bypass connected about the venturi and between the second inlet and the outlet to control water pressure at the first inlet which controls the flow of water in the water return loop.