Abstract: An electric water heating apparatus includes a first electric water heater having a first tank adapted to hold a quantity of water and a first electric heating structure disposed within the first tank. The electric water heating apparatus further includes a second electric water heater having a second tank adapted to hold a quantity of water; and a second electric heating structure disposed within the second tank. The electric water heating apparatus further includes a control unit that is in electrical communication with the first electric heating structure and second electric heating structure, the control unit configured to prevent both the first electric heating structure and the second electric heating structure from being simultaneously operable.

Abstract: The metal tank portion of an electric water heater is protected against corrosion utilizing a corrosion protection system that detects a voltage potential between the sheath portion of a tank water-immersed electric heating element and the tank. In one embodiment of the corrosion protection system the sensed sheath/tank potential is utilized to enable a user of the water heater to accurately gauge the necessity of replacing a sacrificial anode extending into the tank. In another corrosion protection system, the sensed sheath/tank potential is utilized to provide impressed current cathodic protection of the tank and also to prevent dry firing of the electric water heater.

Abstract: A high efficiency downfired gas water heater is provided which has a tank for storing water to be heated, a combustion chamber extending downwardly through a top end of the tank, and a gas burner operative to create hot combustion products within the combustion chamber. At the bottom end of the tank is a transfer chamber coupled to an external discharge conduit and to a single pass heat exchanger, in the form of multiple flue tubes. extending vertically through the tank and connected to the combustion chamber. In one embodiment of the water heater the burner is a power burner which forces the combustion products sequentially through the combustion chamber, heat exchanger, transfer chamber and discharge conduit. In another embodiment of the water heater a draft inducer fan is used to draw the combustion products through this path from the combustion chamber.

Abstract: A heat pump water heater has a tank, a burner in communication with a fuel source, a flue, and a heat pump system. The heat pump system has a refrigerant path, at least a portion of which forms an evaporator in thermal communication with the flue. Another portion of the refrigerant path is in thermal communication with the water tank volume so that heat transfers from the refrigerant to the water tank volume.

Abstract: A high efficiency downfired gas water heater is provided which has a tank for storing water to be heated, a combustion chamber extending downwardly through a top end of the tank, and a gas burner operative to create hot combustion products within the combustion chamber. At the bottom end of the tank is a transfer chamber coupled to an external discharge conduit and to a single pass heat exchanger, in the form of multiple flue tubes. extending vertically through the tank and connected to the combustion chamber. In one embodiment of the water heater the burner is a power burner which forces the combustion products sequentially through the combustion chamber, heat exchanger, transfer chamber and discharge conduit. In another embodiment of the water heater a draft inducer fan is used to draw the combustion products through this path from the combustion chamber.

Abstract: A motor/damper assembly installable on the top end of a fuel-fired water heater includes a support plate structure upon which a flue collar with a pivotally supported flue damper, a drive motor, and a drive shaft interconnecting the motor damper are mounted. The assembly is installed by placing the collar over the upper end of the water heater flue, securing the support plate structure to the top end of the water heater, and positioning a top cover housing on the support plate structure. Using the assembly provides improved support rigidity and alignment for the motor and shaft relative to the damper, improved repeatable precise manufacturing placement of the motor and shaft, improved construction aesthetics, with the cover also protecting the shaft from shipping and handling damages.

Abstract: A motor/damper assembly installable on the top end of a fuel-fired water heater includes a support plate structure upon which a flue collar with a pivotally supported flue damper, a drive motor, and a drive shaft interconnecting the motor damper are mounted. The assembly is installed by placing the collar over the upper end of the water heater flue, securing the support plate structure to the top end of the water heater, and positioning a top cover housing on the support plate structure. Using the assembly provides improved support rigidity and alignment for the motor and shaft relative to the damper, improved repeatable precise manufacturing placement of the motor and shaft, improved construction aesthetics, with the cover also protecting the shaft from shipping and handling damages.

Abstract: A water heater is provided having an insulated tank having a water inlet and a water outlet, and further defining an interior volume to contain a quantity of water. A primary heating arrangement applies heat energy to the water so as to heat the water. In addition, the primary heating arrangement is configured to maintain the water during standby periods between upper and lower set point temperatures. A supplemental heating arrangement is operative to supply additional heat energy to the water in order to lessen energy usage by the primary heating arrangement during the standby periods. In accordance with a preferred embodiment, the supplemental heating arrangement includes at least one photovoltaic panel and a supplemental heating element. Control electronics are operatively interposed between the at least one photovoltaic panel and the supplemental heating element.

Abstract: Water heater apparatus is provided with features that allow for a horizontally compact water heater installation comprising upper and lower vertically stacked electric individual water heaters served by a single electrical branch circuit. Each of the upper and lower water heaters has a water storage capacity not exceeding 55 gallons, and the combined water storage capacity of the upper and lower water heaters is greater than 55 gallons. The electric heating elements of the two water heaters are non-simultaneously controlled so that at no time do the two water heaters heat water at the same time.

Abstract: A tube disposed in the combustion chamber of a standing pilot type fuel-fired water heater is used to increase the overall efficiency of the water heater by improving the heat transfer from the pilot flame to the tank during standby periods by funneling the standing pilot flame upwardly through the tube in a manner concentrating the pilot flame heat against an underside portion of the bottom head of the water heater tank. To further increase water heater efficiency, the pilot burner is of a dual input type. Various pilot burner operational algorithm modes are disclosed for causing the pilot burner to operate at a high firing rate during main burner operation, and at a low firing rate during standby periods.

Abstract: The efficiencies of illustrative embodiments of vertical center flue type fuel-fired base water heaters are improved by installing in the water heaters variously configured tubular condensing type secondary heat exchangers of smaller diameters than the associated center flues. The efficiency increases are achieved with components and manufacturing processes similar to those utilized in the base water heaters and secondary heat exchanger materials similar to those in the tank portions of the base water heaters.

Abstract: The metal tank portion of an electric water heater is protected against corrosion utilizing a corrosion protection system that detects a voltage potential between the sheath portion of a tank water-immersed electric heating element and the tank. In one embodiment of the corrosion protection system the sensed sheath/tank potential is utilized to enable a user of the water heater to accurately gauge the necessity of replacing a sacrificial anode extending into the tank. In another corrosion protection system, the sensed sheath/tank potential is utilized to provide impressed current cathodic protection of the tank and also to prevent dry firing of the electric water heater.

Abstract: In an electric water heater having adjustable set point and differential temperatures, upper and lower heating elements, and associated temperature sensors respectively operative to sense upper and lower tank water temperatures, a specially designed control system is provided for controlling the heating elements. The control system is operative to automatically set a selected setpoint temperature to a second setpoint temperature less than or equal to a predetermined magnitude, and to reduced the second setpoint temperature and/or the differential temperature, as a predetermined function of the magnitudes of detected time intervals between successive heat demands of the water heater, to reduce the energy cost associated with the water heater.

Abstract: In a fuel-fired water heater with a standing pilot burner and a motorized flue damper, a specially designed controller is utilized to prevent overheating of water stored in the tank portion of the water heater caused by the hot combustion gases continuously generated by the pilot burner during standby periods of the water heater in which its main fuel burner is not being fired.

Abstract: A tube disposed in the combustion chamber of a standing pilot type fuel-fired water heater is used to increase the overall efficiency of the water heater by improving the heat transfer from the pilot flame to the tank during standby periods by funneling the standing pilot flame upwardly through the tube in a manner concentrating the pilot flame heat against an underside portion of the bottom head of the water heater tank. To further increase water heater efficiency, the pilot burner is of a dual input type. Various pilot burner operational algorithm modes are disclosed for causing the pilot burner to operate at a high firing rate during main burner operation, and at a low firing rate during standby periods.

Abstract: A high efficiency downfired gas water heater is provided which has a tank for storing water to be heated, a combustion chamber extending downwardly through a top end of the tank, and a gas burner operative to create hot combustion products within the combustion chamber. At the bottom end of the tank is a transfer chamber coupled to an external discharge conduit and to a single pass heat exchanger, in the form of multiple flue tubes. extending vertically through the tank and connected to the combustion chamber. In one embodiment of the water heater the burner is a power burner which forces the combustion products sequentially through the combustion chamber, heat exchanger, transfer chamber and discharge conduit. In another embodiment of the water heater a draft inducer fan is used to draw the combustion products through this path from the combustion chamber.

Abstract: A motor/damper assembly installable on the top end of a fuel-fired water heater includes a support plate structure upon which a flue collar with a pivotally supported flue damper, a drive motor, and a drive shaft interconnecting the motor damper are mounted. The assembly is installed by placing the collar over the upper end of the water heater flue, securing the support plate structure to the top end of the water heater, and positioning a top cover housing on the support plate structure. Using the assembly provides improved support rigidity and alignment for the motor and shaft relative to the damper, improved repeatable precise manufacturing placement of the motor and shaft, improved construction aesthetics, with the cover also protecting the shaft from shipping and handling damages.

Abstract: A water heater is provided with monitor/diagnostic display apparatus that selectively provides a user with visual or other type of indicia of the recovery time for the water heater. The apparatus includes a monitoring unit that may be mounted on the water heater, and a display unit that may be mounted either on the water heater or remotely therefrom.

Abstract: The efficiencies of illustrative embodiments of vertical center flue type fuel-fired base water heaters are improved by installing in the water heaters variously configured tubular condensing type secondary heat exchangers of smaller diameters than the associated center flues. The efficiency increases are achieved with components and manufacturing processes similar to those utilized in the base water heaters and secondary heat exchanger materials similar to those in the tank portions of the base water heaters.

Abstract: A water heater is provided with monitor/diagnostic display apparatus that selectively provides a user with visual or other type of indicia of the remaining hot water availability of, the recovery time for, and the overall efficiency of the water heater. The apparatus includes a monitoring unit that may be mounted on the water heater, and a display unit that may be mounted either on the water heater or remotely therefrom.