Other

David Seitz

Thomas L Harman

David E Seitz

James Huntington Dabney

Louis Everett

David P Sharp

Louis J Everett

Rodney H Neumann

A water heater () is suitable for point-of-use applications. The water heater includes a first temperature sensor, a second temperature sensor, and a controller connected to the first and second temperature sensors. The controller is configured to receive the signals generated by the first temperature sensor and the second temperature sensor and to detect a flow condition of water within the heat without using mechanical flow detection means and without supplying stand-by heating by adding an absolute value of the sensed change in temperature of water at the first temperature sensor to the absolute value of the sensed change in temperature of water at the second temperature sensor to yield a sum and then comparing the sum to a reference temperature.

Tankless water heater

A water heater with a housing having an internal chamber, an inlet port, and an outlet port; a heating element coupled to the housing; a water inlet line; a water outlet line; an inlet temperature sensor within the water inlet line; an outlet temperature sensor within the water outlet line; and a controller electrically connected to the inlet temperature sensor, the outlet temperature sensor, and the electrically power heating element. The controller is operable to detect a flow condition without using mechanical flow detection means and without supplying stand-by heating by adding an absolute value of the sensed change in temperature of water flowing upstream from the inlet port to the absolute value of the sensed change in temperature of the water flowing downstream from the outlet port to yield a sum and comparing the sum to a reference temperature.

An improved system, method and apparatus for control of an instantaneous flow-through fluid heater system is disclosed. The control incorporates a logic control method providing modulation of power in small steps to a plurality of heating elements retaining responsiveness to closed-loop control needs without inducing light flicker. Further, the life of the coils of heating circuit electromechanical relays are extended by energizing the coils with a pulse-width-modulated drive decreasing in duty cycle and thus the latent coil heat when an increase in mains voltage is sensed. The life of the contacts of same relays are extended by inhibiting heating element triac drive immediately upon sensing loss of relay coil power, such as by an over temperature limit switch opening, thus ensuring that relay contacts open with zero heating element current. In addition to the software &ldquo;watchdog timer&rdquo; internal to the microcontroller, a redundant fail-safe circuit external to the microcontroller prevents a program lockup condition from leaving any heating element triac or relay drive in an energized state. A combination of control hardware and program provide self-diagnostic detection of an inoperative thermistor, stuck relay, or a failed triac or heating element. An improved means of sensing water level is disclosed incorporating a low-level, high frequency signal, allowing detection of non-conducting distilled water and the reliable detection of water in the presence of main-frequency currents as would exist in ungrounded sheathed heating elements with electrical leakage or as would exist with bare-elements.

Growing community of inventors

Houston, TX, United States of America

Thomas L Harman