Abstract: A microcomputer operates in response to user selected flow rate and water temperature inputs to calculate the temperature difference between the cold water input and the hot water delivery output from a multisection continuous flow electric water heater wherein a plurality of electric resistance heater elements contained therein provide 5.degree. F. temperature increase increments each, while one heater element is comprised of three sub-sections, two of which provide 2.degree. F. temperature increments and one section provides a 1.degree. F. temperature increase increment. The microcomputer constantly monitors the water temperature difference and controls activation of the required heater elements or element sub-sections to heat the water to a selected delivery temperature with an output solenoid being additionally controlled to provide delivery at a selected flow rate.

Abstract: An electric instant water heater mounted in a cold water line in proximity to a water tap includes an elongated core molded from a ceramic material and having a rectangular cross-section water flow passage extending therethrough from a circular inlet connected to a water supply pipe to a circular outlet connected to the water tap. A plurality of parallel, spaced, thin rectangular electrical resistance heating plates are positioned within the passage with one rolled edge of each plate being embedded in the core on one side of the passage way and the opposite rolled edge of each plate extending freely into the passage. A plurality of projections molded integrally with the core extend from the opposite side of the passage into the spaces between the heating plates and terminate short of the one side of the passage to define with the plates a serpentine flow path from the inlet to the outlet to cause water to be heated to flow across each face of the heating plates.