A water heater includes an inner water tube coil and an outer water tube coil separated by a drum baffle. The inner and outer coils extend above a top edge of the drum baffle by at least a full turn of each coil. A flue gas bypass path is defined between a top edge of the drum baffle and a top insulation layer above the inner and outer coils. Flue gases flow radially though the inner coil, up along the drum baffle, through the flue gas bypass path, and downwardly over the outer coil to heat water flowing through the inner and outer coils. The water flows into the outer coil at the bottom of the coil, winds upwardly through the outer coil in countercurrent flow with respect to the flue gases, then down through the inner coil.

A water heating apparatus includes a sensor to detect an inflow water amount flowing into the water heating apparatus, and a controller to determine connection or disconnection between the water heating apparatus and a water storage tank, based on the inflow water amount flowing into the water heating apparatus for a preset time duration. Thus, the water heating apparatus determines whether or not the water storage tank is connected thereto based on the amount of inflow water introduced into the water heating apparatus. Then, the water heating apparatus determines the operation mode of the water heating apparatus based on the determination result. Thus, even when the user incorrectly sets the operation mode of the water heating apparatus, the water heating apparatus may actively and correctly operate.

A multi-temperature output fluid heating system including an input for receiving a fluid supply, a single heating source, a first output, a second output and a bypass path. The first output is fluidly connected to the input, where the first output is adapted for control by a first control device and to receive heat from the single heating source to achieve a first temperature at the first output. The bypass path fluidly connects the input and the second output. The input is adapted to empty a first portion of the fluid supply into the first output and a second portion of the input into the bypass path. The second output is adapted to receive an output from the first output and an output from the bypass path to achieve a second temperature.

Apparatuses of an energy efficient water heater and methods for controlling the same are disclosed. In one embodiment, a water heater may include a water inlet configured to receive input water, an input water temperature sensor configured to detect a temperature of the input water, a user interface unit configured to receive an output water temperature setting selected by a user, a controller configured to determine a flow rate of an output water based on the input water temperature and the output water temperature setting, a heating unit configured to heat the input water to produce the output water, the controller is further configured to control the heating unit and a proportional flow restrictor to produce the flow rate of the output water, and a water outlet configured to transfer the output water at the flow rate of the output water.

A water heater includes an inner water tube coil and an outer water tube coil separated by a drum baffle. The inner and outer coils extend above a top edge of the drum baffle by at least a full turn of each coil. A flue gas bypass path is defined between a top edge of the drum baffle and a top insulation layer above the inner and outer coils. Flue gases flow radially though the inner coil, up along the drum baffle, through the flue gas bypass path, and downwardly over the outer coil to heat water flowing through the inner and outer coils. The water flows into the outer coil at the bottom of the coil, winds upwardly through the outer coil in countercurrent flow with respect to the flue gases, then down through the inner coil.

A hot water supply system decouples an intelligent hot water storage system from a water heating engine system. The water heating engine system includes a plurality of instantaneous water heaters that provide for redundant operation for improved reliability. The intelligent hot water storage system includes a storage tank that encloses a volume for storage of water. The intelligent hot water storage system includes a recirculation loop driven by an integrated pump and operated by an integrated controller. By positioning the tank recirculation outlet and inlet farther apart from each other, additional usable volume of hot water is provided by the intelligent hot water storage system. Isolation valves positioned on the input and output of a recirculation pump in the recirculation loop facilitate repair or replacement of the recirculation pump. The hot water system provides for increased capacity while providing redundant heating engines in a smaller floor space than conventional systems.

A vent attachment facilitates attaching a coaxial air intake and exhaust vent of a tankless water heater to a Category I vent, such as B-vent. The vent attachment comprises a first end with a coaxial connector comprising a central exhaust pathway and a circumferential air intake pathway. The vent attachment also comprises a second end with a tubular exhaust vent connector in fluid communication with the central exhaust pathway. The vent attachment further comprises a frame that encloses the central exhaust pathway and comprises a mesh configured to provide fluid communication through the frame with the air intake pathway. Additionally, operation of the tankless water heater is modified to ensure that the exhaust generated is suitable for venting through a Category I vent. The tankless water heater maintains a high fuel consumption rate such that the temperature of hot water produced increases throughout each of a plurality of burner stages.

Systems and methods for controlling the output water temperature of a water heater are disclosed herein. The water heater preferably has a water inlet, heating unit, and water output. The system comprises a proportional flow restrictor placed near the water output and a controller which is configured to direct the heating unit to heat the water and the proportional flow restrictor to produce a flow rate of the output water. Temperature sensors may be used to control the proportional flow restrictor. The proportional flow restrictor can also be controlled based on the amount of heat energy applied to the heating unit.

An offset mounting bracket that comprises a primary member and a stabilization member can be used to mount multiple heat engines to a water storage tank. An offset mounting bracket can include a primary member, having a top surface, a bottom surface, an inner surface, and an outer surface. The offset mounting bracket can also have a stabilization member, having a top surface and a bottom surface, a supporting surface that is opposed and connected to the primary member outer surface. The offset mounting bracket can also have a connecting member. The connecting member can be configured to fasten to the top of a water storage tank. There, the offset mounting bracket, can provide a surface to mount a heat engine that otherwise would not fit onto the water storage tank structure.

A boiler includes a tank, a gas circuit that includes a main combustion chamber in the tank and branch tubes in the tank that extend off of the main combustion chamber, and a water circuit fluidly isolated from the gas circuit. The water circuit includes a first manifold and water tubes that extend off of the first manifold. Each water tube extends through a respective one of the branch tubes, which may serve to preheat the water prior to discharge of the water into the tank.