Abstract: A liquid heating system includes an instantaneous heater (18) having an inlet (20) connected to a reservoir (62). The outlet (22) of the heater is connected to fixtures (72) which use the heated liquid, and is also connected through a return connection (30) to the reservoir. In an idle mode, a pump 40 draws liquid from the reservoir (62), so that the liquid circulates through the heater and back to the reservoir. A controller (52) actuates the heater to heat the liquid to a first setpoint temperature, so that the liquid in the reservoir stabilizes at the first setpoint temperature. In a supply mode, some or all of the heated liquid flows from the outlet to the fixtures (72). Cold liquid is admitted from a supply (60) to the reservoir, and cold liquid desirably also is supplied to the heater inlet along with liquid from the reservoir, so that the heater inlet receives a combination of these.

Abstract: A mixing valve arrangement for a hydraulic system is provided with a medium cavity, in which a mixing cylinder, a first and a second inlet chamber as well as an outlet are provided. A mixing piston is axially mounted and movable in the mixing cylinder, provided with a flow path with an inlet opening, a variable cross-section of said inlet opening culminating into the first and/or the second inlet chamber, according to the axial position of the mixing piston, and with an outlet opening culminating in the outlet of the mixing cylinder. A thrust rod is axially mounted and movable and connected to the mixing piston, to change the axial position thereof. A drive is connected as an actuator to the thrust rod, for the axial movement of the same. The drive is an electrical motor, which is completely arranged inside the medium cavity.

Abstract: A water heater includes a tank containing water to be heated and a thermal displacement conduit communicating between a portion of the tank and a receptacle. Water is displaced out of the portion of the tank, through the conduit, and to the receptacle during thermal expansion of the water during heating.

Abstract: A water heater appliance includes a tank and a heated water conduit extending from the tank. A mixing valve is coupled to the heated water conduit, and a heat trap is mounted to the heated water conduit upstream of the mixing valve. The heat trap includes a membrane disposed within the heated water conduit. The membrane of the heat trap may assist with obstructing recirculation of heated water from the tank into the heated water conduit.

Abstract: A system is provided that allows relatively low temperature water to be withdrawn from a pipeline, heated and then returned to the pipeline. At least one embodiment includes a device for adjusting the rate of flow through a primary pipe so that desired temperatures are maintained during the heating process.

Abstract: A cold water intake pipe 4 and a hot water extraction pipe 5 that communicate with multiple spiral tubes 101 and a steam supplying pipe 2 and a condensate discharge pipe 3 that communicate with a shell are connected to a corrugated spiral tube type heat exchanger 1. Between the cold water intake pipe 4 and multiple spiral tubes 101, communication paths 46 that communicate between the cold water intake pipe 4 and some multiple spiral tubes 101a are provided, and a valve 44 is provided to communicate between the cold water intake pipe 4 and the other multiple spiral tubes 101b when the force acting from the cold water intake pipe 4 becomes larger than the force acting from the other multiple spiral tubes 101b and to block the cold water intake pipe 4 from the other multiple spiral tubes 101b when the force acting from the cold water intake pipe 4 becomes smaller than the force acting from the other multiple spiral tubes 101b.

Abstract: A steam boiler includes a boiler housing. A helical coil for boiling water and superheating the wet steam is disposed within the boiler housing. A burner emits combustion gases which heat a heat emitter which is disposed in the inner space of the helical coil. Combustion gases from the burner enter the internal cavity of the heat emitter and then pass through perforations in the heat emitter before contacting the helical coil. As such, the heat emitter is heated by the combustion gases and serves as a radiant heat source for the helical coil.

Abstract: Embodiments of the present invention provide improved heating methods for use in coffee makers and other beverage makers that use hot water for various beverages and other purposes. These improvements find particular use on-board aircraft or other passenger transport vehicles, where quick heating and reduced power consumption are particularly desirable and beneficial. Further embodiments also relate to improved water level sensing, improved water reservoirs, and improved carafe features.

Abstract: An apparatus for heating water and steam, that has a first container with cold water and a second container with hot water, the two containers being in fluid communication via an intermediary pipe having a one-way valve to permit flow only from the first container to the second container. The first container has a water level monitor that controls when an input pipe allows water to refill the first container. The second container has a heat exchanger, a steam input pipe, a steam output pipe, and a heating element. The second container may be connected to a steam press, a boiler, and a washing machine.

Abstract: There is provided an indoor mounting water heater in which combustion exhaust gas is discharged to the outdoors via an exhaust duct, wherein a decrease in draft force caused when the number of burner groups to be burned is reduced by a capacity changeover mechanism to decrease the combustion capacity can be prevented, and the heat efficiency can be improved. An air supply chamber 81 is divided into a plurality of parts 82 and 83 corresponding to a plurality of burner groups 51 and 52. The air sent from an air supply fan 84 is supplied to only a part of the air supply chamber corresponding to a burning burner group.

Abstract: A water heater capable of suppressing an increase in the combustion air temperature exiting the heater and the generation of nitrogen oxide within an easy structure is provided. In the water heater, a burner is provided in a combustion chamber which is below a hot water storage chamber that is an all primary air burner which takes in the air required for gas combustion, whereby the air is mostly primary air. In addition, the burner is provided with a supporting plate in the combustion chamber at a height that allows part of the burner head to be protruded into a space covered by a lower mirror plate.

Abstract: The present invention relates to a portable boiler for a hot mat, which comprises: a water reservoir, one side of which has an inlet pipe for introducing water circulating through the hot mat, and which stores the water; a heat transfer unit in which the water discharged from the water reservoir flows along a flow channel pipe to be heat exchanged, wherein the water is discharged to the hot mat via an outlet pipe formed at one side thereof; a heating unit which burns the fuel gas fed from a fuel tank to heat the water in the heat transfer unit; and a housing which forms the outer appearance of the boiler.

Abstract: A pipe fitting is connected in a conduit from a source of fluid under pressure. The pipe fitting comprises a tubular body defining an elongate interior chamber open at both an upstream end and a downstream end. The wall of the body defines a plurality of radial passages opening into the interior chamber and extending through the wall at an acute angle relative to the longitudinal axis of the body. The passages open to the atmosphere through the wall axially spaced upstream from the passage openings into the interior. Fluid flows through the body from the upstream end to the downstream end without escaping through the passages. When fluid flow is blocked downstream of the body, backflow of fluid is directed radially outwardly and angularly upstream through the passages to the atmosphere.

Abstract: A commercial hot water system includes a boiler, a storage tank, and a hot water delivery line connected between the storage tank and at least one plumbing fixture along with a cold water delivery line connection between said plumbing fixture, a cold water source and said boiler. A pump, interconnected between the hot and cold water delivery lines, enables circulation of water to the fixtures. A timer and controller provides for turning on the pump and a temperature sensor, connected to the controller, is effective in stopping the pump to prevent heated water from being circulated through the cold water line.

Abstract: A fuel-fired water heater is provided with a premixing type main burner and an associated pilot burner for igniting it. A specially designed protective system is operative to detect a flame flashback burning condition in the main burner and responsively shut down the water heater. In one embodiment thereof, the protective system uses main burner body heat to melt a portion of a fuel supply line connected to the pilot burner during a flame flashback condition in the main burner. Such melting responsively causes an associated fuel supply valve to close and terminate water heater operation. In a second protective system embodiment a normally closed pressure switch is opened, thereby shutting down the water heater, when the switch detects a pressure indicative of a flame flashback condition in the main burner.

Abstract: A combustion apparatus 51 includes a plurality of burners 58, a plurality of fuel supply channels 89, a blower 53, an air supply passage 37, and a pressure regulator 56. The burners 58 are divided into a plurality of burner groups 71. The pressure regulator 56 is branched at a portion located immediately after a gas outlet 31 at downstream of the regulator 56 and connected to the respective fuel supply channels 89, so as to regulate gas supplied at a primary pressure to gas at a secondary pressure in response to a predetermined signal pressure sensed from one selected from a part of the air supply passage 37 and the blower 53 and to discharge the regulated gas through the pressure regulator 56. The fuel supply channels 89 each are configured to perform fuel supply to the respective burner groups 71 and are provided with a switching valve 75 for either shutting off or reducing the fuel supply to at least a part of the burner groups 71.

Abstract: A fuel-fired water heater has main and pilot burners disposed in its combustion chamber. Illustratively, all of the primary combustion air utilized by the main and pilot burners during firing thereof is supplied thereto via an enclosed path extending to the burners from outside of the combustion chamber. A burner clogging detection system is operative to shut down further combustion, upon sensing a condition of the pilot burner flame indicative of a predetermined degree of pilot burner clogging, prior to the main burner being clogged to an unacceptable degree by particulate matter entrained in incoming combustion air being delivered to the main burner.

Abstract: A water heater includes a sealed combustion chamber and one or more fans for raising pressure in the combustion chamber to increase efficiency of the water heater. The pressure permits a more restrictive baffle to be used in the flue compared to baffles used in atmospheric water heaters. The water heater may include a water temperature sensor that activates the fan without activating the burner if water temperature raises above a desired temperature. The water heater may also include pressure and vapor sensors to ensure the combustion chamber is properly sealed and there are no flammable vapors present prior to igniting the burner. The fans are relatively small and run off the same DC power that runs an electric gas valve. The fans may be, for example, 12 or 24 Volt fans with power inputs of about 10 Watts or less.

Abstract: A control system is provided for a modulated heating system including at least one modulating water heater and a controller. A deadband control scheme provides for reduced cycling of the modulating heater when total system heat demand falls between the maximum output of one heater and the sum of the maximum output of that one point and the minimum firing point of the next subsequent heater. Condensation of flue gas products is prevented by monitoring flue exhaust temperature for each heater and controlling the modulation of each heater to maintain a minimum heater output sufficiently high to prevent condensation of flue gas products from that heater. Rapid reaction to changes in system heat demand is provided by sensing changes in flow rate in a primary loop of the system and anticipating resulting changes in temperature thus allowing for change in heater output prior to the time the change in flow rate has fully impacted system temperature.

Abstract: A liquid heating appliance, representatively a water heater, is provided with protective apparatus for preventing rupture of its liquid storage tank portion caused by overheating of pressurized liquid therein. Illustratively, the protective apparatus includes a length of thermoplastic tubing, preferably polybutylene tubing, whose interior is exposed to the tank interior so as to be pressurized by heated liquid therein. In the event of a liquid overheating condition in the tank, the tubing is heat-softened in a manner reducing its burst pressure and causing it to burst, at a pressure substantially below the tank burst pressure, and thereby form a pressure relief outlet passage for the tank. A shield structure with at least one fluid outlet opening therein extends outwardly around the thermoplastic tubing to diffuse pressurized fluid escaping from the burst tubing.

Abstract: A radiant gas burner within the combustion chamber of a water heater has a pilot flame created using a cross-sectionally elongated raw fuel jet that impinges on an interior surface portion of a flame holding outer burner wall portion, representatively of a metal wire mesh material, and is mixed within the burner with combustion air delivered thereto from outside the combustion chamber. The resulting fuel/air mixture passes outwardly through the impinged upon mesh wall portion, which functions as a pilot flame stabilizing structure, and is ignited to form a pilot flame on the exterior of the burner body. A thermocouple portion of a clogging detection system senses a change in the pilot flame shape caused by particulate clogging of the metal mesh material and responsively terminates further gas supply to the water heater.

Abstract: A control system for a fuel-fired water heater appliance is provided that includes a control for the appliance that is in communicating with a sensor for sensing a water flow rate through the water heater. The control system is capable of controlling a gas valve to supply fuel to a burner at a maximum rate of fuel flow when the water flow rate is determined to be above a predetermined threshold. The control system is capable of controlling the gas valve to supply fuel to a burner at a reduced rate of fuel flow when the water flow rate is below a predetermined threshold, whereby the control 128 establishes the lower rate of heating operation as long as the temperature of the heated water is below the predetermined maximum temperature.

Abstract: An object of the present invention is to provide a combustion apparatus capable of certainly detecting a shortage of an amount of air relative to that of fuel gas. A combustion apparatus 1 is adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air 67, including a first ion current measuring element 65 positioned at a site where a flame of the primary combustion is to take place and a second ion current measuring element 66 adjacent to a secondary air supply opening 20, 21, 63, or 64 for supplying the secondary air 67, so as to control at least one selected from a group consisting of (a) a ratio of an amount of the primary air to that of the secondary air, (b) a total amount of the primary and the secondary air, and (c) an amount of the fuel gas based on measured values by the first and the second ion current measuring elements 65 and 66.

Abstract: A heat trap assembly for providing a thermal dam within piping associated with water heaters is disclosed. The heat trap includes an elongated housing, a fin and a flap member. The housing includes first and second ends, and an interior opening extending therethrough to define an internal passage. The fin has a multi-sided body and is fixedly inserted into the housing. The flap member has a flexible disk-shaped body with first and second faces, an outer peripheral edge and an aperture disposed inward of the outer peripheral edge. A portion of the fin is inserted through the aperture. The outer peripheral edge is essentially contiguous with an interior wall surface of the housing in the absence of water flow within the internal passage, and is bendable in a direction of flow when water is flowing toward the first face or the second face.

Abstract: The present invention involves a water heater and method of manufacturing the same. The water heater includes a tank assembly and a base assembly. The base assembly includes a heater assembly, a control unit, a control circuit and at least one temperature sensor. The base assembly is a separate module that has at least the heater assembly and control unit mounted thereto.

Abstract: A low NOx water heater including a water container; a combustion chamber adjacent the water container; and a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container, the burner comprising a plenum chamber having a combustion surface and a device to detect the presence of the collection of lint, dirt and/or oil.

Abstract: In a flammable vapor sensor-based shut-off system of a fuel-fired water heater the sensor resistance output signal degradation caused by aging of the sensor is automatically compensated for using an operational timer having an output signal indicative of the total life of the sensor subsequent to its installation on the water heater. In one embodiment of the system, a resistance adjustment signal having a magnitude related in a predetermined manner to the timer output signal is created and added to the sensor resistance output signal. In another embodiment, the timer output signal is used to appropriately adjust the minimum-maximum received sensor signal magnitude range, based on the installed age of the sensor, which will preclude combustion in the appliance. Additionally, in each embodiment thereof the system is provided with an improved initial minimum-maximum sensor signal magnitude range. Other types of shut-off gas sensors may be alternatively utilized.

Abstract: A radiant burner within the combustion chamber of a fuel-fired water heater is supplied with primary and secondary combustion air from outside the combustion chamber. A flame-holding mesh section of the burner is protected from becoming unacceptably clogged by particulate matter in the primary combustion air by causing the incoming secondary combustion air to flow sequentially through a finer mesh section and a tapered duct which increases the velocity of the secondary combustion air before causing it to impinge upon and cool a temperature sensor connected to a controller. Clogging of the finer mesh section decreases the cooling of the temperature sensor, thereby causing the controller to terminate operation of the burner before it becomes unacceptably clogged.

Abstract: A fuel-fired water heater has main and pilot burners disposed in its combustion chamber. All of the primary combustion air utilized by the main and pilot burners during firing thereof is supplied thereto via an enclosed path extending to the burners from outside of the combustion chamber. A burner clogging detection system is operative to shut down further combustion, upon sensing a condition of the pilot burner flame indicative of a predetermined degree of pilot burner clogging, prior to the main burner being clogged to an unacceptable degree by particulate matter entrained in incoming combustion air being delivered to the main burner.

Abstract: A heat trap assembly for a hot water tank includes a heat trap insert and a sealing member retained by the heat trap insert. The heat trap insert includes a seat having an opening that is dimensioned to be covered by the sealing member when no water is flowing through the assembly. The heat trap insert also includes a plurality of fingers to retain the sealing member when water is flowing through the heat trap assembly.

Abstract: A water heater includes a sealed combustion chamber and one or more fans for raising pressure in the combustion chamber to increase efficiency of the water heater. The pressure permits a more restrictive baffle to be used in the flue compared to baffles used in atmospheric water heaters. The water heater may include a water temperature sensor that activates the fan without activating the burner if water temperature raises above a desired temperature. The water heater may also include pressure and vapor sensors to ensure the combustion chamber is properly sealed and there are no flammable vapors present prior to igniting the burner. The fans are relatively small and run off the same DC power that runs an electric gas valve. The fans may be, for example, 12 or 24 Volt fans with power inputs of about 10 Watts or less.

Abstract: A radiant gas burner within the combustion chamber of a water heater has a pilot flame created using a raw fuel jet that impinges on an interior surface portion of a flame holding outer burner wall portion, representatively of a metal wire mesh material, and is mixed within the burner with combustion air delivered thereto from outside the combustion chamber. The resulting fuel/air mixture passes outwardly through the impinged upon mesh wall portion, which functions as a pilot flame stabilizing structure, and is ignited to form a pilot flame on the exterior of the burner body. A thermocouple portion of a clogging detection system senses a change in the pilot flame shape caused by particulate clogging of the metal mesh material and responsively terminates further gas supply to the water heater.

Abstract: The water heater has an upright water tank (1), an exhaust flue (3) extending through the water tank, a combustion chamber (2) arranged under the water tank, an atmospheric gas burner (5) in the combustion chamber and a complete pre-mixing gas/air supply system with outside gas and air intakes. The gas burner has a burner mat (7) with a pressure drop less than 5 to up to 45 Pa. The combustion chamber (2) is provided with an opening (2b), which is not sealed, but enclosed in a flame-blocking manner. The gas burner (5) is attached to a wall section (2a), which is mounted releasably on the: combustion chamber wall (W) over opening (2b) so that a gap of predetermined width is formed between the wall section and wall (W), which prevents backfire of flames into the surroundings but admits secondary air.

Abstract: A secondary burner is provided in a sealed combustion chamber of a gas-fired hot water heater. The hot water heater has a support base for supporting it elevated from a floor surface. The sealed combustion chamber is supported over the base under an inner casing of the hot water heater which is adapted to contain water to be heated by a primary burner in the combustion chamber. An air inlet port is provided in the bottom wall of the combustion chamber to supply combustion air to the primary burner. The secondary gas burner perforated disc is secured entirely across the air inlet port and in direct unobstructed communication with the primary burner. The secondary gas burner perforated disc has holes throughout its inner surface whereby to ignite its an inner surface thereof in the presence of flammable vapors and air entering the gas burner perforated disc from an outer surface thereof. The support base has air inlet openings to permit ambient air supply to the outer surface.

Abstract: A portable instant water heater. Water is delivered to a base unit of the instant hot water heater by a pump that draws water from a reservoir through a flow control valve. The water flows into a pre-heater that wraps around a base of the burner and that is heated by the burner. Water is heated in a heat exchanger and then exits the base unit through an outlet spout that swings out from the base unit to dispense water and that may be stored and locked into position in a handle for the base unit. The flow control valve may lower the flow of water through the heat exchanger, so the water has more time to absorb heat and to get hotter. The base unit includes a single control knob that turns on the pump and the burner and operates the flow control valve.

Abstract: A fuel-fired, power vented water heater has a combustion chamber with an outer wall portion defined by an arrestor plate in which flame quenching air inlet openings are formed. All combustion air entering the combustion chamber must first pass through an air inlet plenum extending outwardly from the arrestor plate and then pass inwardly through the flame quenching openings into the combustion chamber. The air inlet plenum is provided with a normally closed inlet damper which automatically closes during non-firing periods of the water heater to prevent passage of combustion air (and extraneous flammable vapors, if present, adjacent the water heater) into the combustion chamber, and opens during firing periods of the water heater to permit operative combustion air delivery to the combustion chamber.

Abstract: A heat trap assembly for a hot water tank includes a housing and a sealing member disposed in the housing. The sealing member includes a first portion that is adapted to restrict rotational movement of the sealing member in at least two perpendicular axes. The sealing member includes a second portion that is adapted to restrict rotational movement in a third axis perpendicular to both of the at least two perpendicular axes.

Abstract: A hot water tank monitoring system is designed to shut off the water supply to the hot water tank and to shut off either the electrical supply or the gas supply to the heating unit of the hot water tank in response to sensing of malfunction of one or more of a number of different sensed parameters. These parameters include a water leak detector located beneath the water tank, a water level float sensor, a temperature sensor to sense excess temperature, and a pressure sensor located in the line between the pressure relief valve and the blow-out outlet of the water tank. Signals from the various sensors are supplied to a controller, which provides signals to a LED status indicator, and also operates to provide alarm signals through a modem over telephone lines to remote locations and to operate an alarm.

Abstract: Convective heat traps are installed at the cold water inlet and hot water outlet of a water heater. Each heat trap has a tubular body with two axially spaced apart resilient flapper members transversely extending across the interior of the body and being hinged on opposite sides thereof. The heat trap at the cold water inlet is coaxially disposed within a dip tube. In one alternate structure, flapper members are mounted directly on the dip tube, and in another alternate structure an external annular seal element is mounted on the dip tube or heat trap body, with a flapper member being integrally formed with the seal element.

Abstract: A heat trap assembly for a hot water tank includes a housing and a sealing member disposed in the housing. The sealing member includes a first portion that is adapted to restrict rotational movement of the sealing member in at least two perpendicular axes. The sealing member includes a second portion that is adapted to restrict rotational movement in a third axis perpendicular to both of the at least two perpendicular axes.

Abstract: An improved gas-fired water heater is disclosed which comprises a sealed cylindrical shell extending from the base of the water tank to the top, enclosing the burners and controls so as to shield them from flammable vapors in the immediate vicinity. The cylindrical shell forms an annular passage outside the tank (and insulation, if present), which facilitates the intake of combustion air. This annular passage is shielded from above and the side adjacent the top of the tank by a cover fitted to the tank top which extends downward from the top to form a lip which laterally shields the annular passage and directs intake combustion air upward from outside the shell to enter the annular passage. The bottom of the heater can be extended by a cylindrical skirt extension which encloses the burner of the heater in an airtight manner except for air inlets in the bottom of the extension.

Abstract: A brown gas combustion apparatus and heating system using the same is provided in which a brown gas generated from a brown gas generator flows into a water-tight flame arrester filled with hexane(C6H14) of hydrocarbon systems so as to mix the brown gas with a small amount of hexane gas, to thereby delay the combustion speed and fundamentally prevent flash-back or back-fire. The brown gas combustion apparatus includes a heating unit which is directly heated by a burner and radiates heat. The heating system includes the combustion apparatus installed upright therein, and is configured in that the high temperature water molecules scattered from the combustion apparatus absorb the infrared ray radiated from an infrared ray radiation member within the combustion chamber, and oscillate in an ultra high temperature by self-heating.

Abstract: A control method of a thermostatic system for a hot water heater is provided where when the water temperature in the hot water heater is too large, a first electromagnetic valve is controlled to be open and a second electromagnetic valve is controlled to be closed. Gas will be transferred via the first gas room to the second gas room. The control of the electromagnetic valves causes a decrease in gas outflow to the hot water heater. When the water temperature in the hot water heater is too small, the first electromagnetic valve is controlled to be closed and the second electromagnetic valve is controlled to be open. The further control of the electromagnet valves causes an increase in the open degree of a gas outlet valve, hence increasing gas outflow.

Abstract: A water heater including a water container having an inlet and an outlet; a main burner positioned to heat water in the water container; a pilot burner positioned to supply flame to the main burner; and a control valve to supply fuel to the main and pilot burners.

Abstract: There is provided a water heater unit realizing antifreezing of a water tube and the like of a heat exchanger without providing a backwind stopper on an exhaust tube. The water heater unit comprises a heat exchanger for heating water by a combustion heat of combustion means, water temperature sensors for detecting the temperatures of the water tube connected to the heat exchanger and an air supply fan for supplying air to a combustion chamber in which the combustion means is installed. When temperatures detected by the temperature sensors reach a temperature at which freezing of the heat exchanger is expected, the air supply fan is driven to supply air to the combustion chamber and the air is exhausted toward an exhaust port, thereby effecting heat exchange and antifreezing of the water tube.

Abstract: A single control device is operational to control the flow of gas to a water heater as well as to protect against excessive temperature and pressure. The control device requires only a single fitting to be attached to the water heater tank to expedite the assembly process, eliminate a number of potential sources of leakage and reduce heat loss.

Abstract: A flapper-type anti-siphoning check valve for a domestic water system has an auxiliary valve built into the flapper. The auxiliary valve permits slow reverse flow of water through the check valve when the flapper is closed to prevent build-up of pressure in the user's water system, but closes as a result of more rapid reverse flow of water in the event of a sudden drop in supply pressure.

Abstract: A water heater includes a storage tank communicating with a cold water supply pipe and a hot water supply pipe for the respective supply of cold water to, and removal of hot water from, the tank. The water heater also includes an insulated heat recovery module communicating between the cold water supply pipe and the tank. The heat recovery module defines a cavity, and the cold water supply pipe communicates with a lower portion of the cavity. The heat recovery module has a smaller surface area-to-volume ratio than the cold water supply pipe. When water in the tank is heated, some water is thermally displaced from the tank and into the cavity. Consequently, water is displaced out of the lower portion of the cavity and into the cold water supply pipe. Therefore, only the coldest water is displaced out of the cavity, and thermal energy loss is reduced.

Abstract: A water heater including a water container; a combustion chamber adjacent the container, the combustion chamber having at least one air inlet to admit air and extraneous fumes into the combustion chamber and confine ignition and combustion of the extraneous fumes within the combustion chamber; a burner associated with the combustion chamber and arranged to combust fuel to heat water in the container; and an air diverter positioned between the air inlet and the burner and adapted to channel at least a portion of combustion air passing through at least a portion of the air inlet to a position for mixture with the fuel prior to entering the burner to slow combustion and thereby reduce combustion temperatures and NOx emissions.

Abstract: A water heater including a water container having an inlet and an outlet; a main burner positioned to heat water in the water container; a pilot burner positioned to supply flame to the main burner; and a control valve to supply fuel to the main and pilot burners.