Water heating system

Abstract

A water heating device comprising (a) combustion means for igniting a combustible mixture of air and gas for heating water; (b) heat exchanger means for providing heat transfer between the hot gases and the water, the exchanger means including a combustion chamber for receiving the hot gases, a water chamber having an inlet and outlet between which water passes, the water chamber enclosing the combustion chamber, and a plurality of exchange tubes connected to the bottom of the combustion chamber, the tubes extending below the combustion chamber and through the water chamber, such that the hot gases flow through the combustion chamber and then through the tubes in physical isolation from and in heat exchange relation with the water, and the water flows about the tubes and then around the outside of the combustion chamber in counterflow to the hot gases; and (c) temperature control means for controlling the temperature of the water, including thermal measuring means having a sensor for sensing the temperature of outgoing portions of the water, and controlling means responsive to the sensed temperature for controlling the rate of heat transfer between the fluids by modulating the flow of air and gas to the combustion means.

Dependencies are inferred from the claim text.