Water heater

Claim 1

A water heater comprising: an elongated vessel having an open end and a closed end; heat exchange means received within said open end and defining within the vessel a heat exchange zone occupying the major portion of the volume of the vessel and leaving the minor portion of the volume of the vessel for a storage and blending zone adjacent the closed end of the vessel, the heat exchange means including a bundle of elongated heat exchange elements spaced over substantially the full cross-sectional extent of the vessel, said cross section being perpendicular to the direction of elongation of the vessel, and extending from said open end towards said closed end over the major portion of the length of the vessel; a cold water inlet located adjacent said open end of the vessel; a hot water outlet located adjacent said closed end of the vessel in the storage and blending zone and remote from the heat exchange zone; means for recirculating water through the heat exchange zone of the vessel including a recirculation conduit, the conduit having an inlet located within the vessel closely adjacent the inner end of the bundle of heat exchange elements for drawing water essentially solely from the heat exchange zone of the vessel and an outlet communicating with the vessel adjacent said open end thereof for conduction of water into and through the heat exchange zone; and control means for controlling the input of heat to the heat exchange means in response to temperature changes in the water coming from the heat exchange zone of the vessel, the control means including a temperature sensor received entirely within the recirculation conduit such that it is responsive to a high velocity flow of water drawn essentially solely from the heat exchange zone of the vessel.