Abstract: A method and an apparatus are provided for preventing coagulation in an exhaust pipe of a boiler is provided. The method includes operating the boiler and executing a combustion stroke, determining if an ambient air temperature measured by an ambient air temperature detecting sensor is equal to or lower than a first temperature, shifting a 3-way valve to a hot-water location if the measured ambient air temperature is equal to or lower than the first temperature, executing an extinction stroke of a burner if the temperature of space heating water reaches a second temperature, and operating a circulation pump and a blower to exchange heat in a heat exchanger and to discharge warm air through an exhaust pipe, thereby preventing coagulation in the exhaust pipe of the boiler.

Abstract: A portable tankless water heater includes a heat exchanger disposed in a sealed housing with an inlet cold water line and an outlet hot water line extending outside the sealed housing. A burner, disposed in an operative relationship with said heat exchanger is provided for heating water flowing through said heat exchanger and an exhaust system induces draft of air from a housing air inlet through said heat exchanger and out of a housing flue outlet.

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 hot water heater, particularly but not exclusively for domestic use, is herein described and having removably secured thereto a modular heat exchanger or an external water heater to heat the water in a separate tank portion. The two are easily separable from one another for service, repair or interchange. The air-to-air heat exchanger extracts heat loss from the central flue of a gas fired water heater to provide a source of heat for the building in which the hot water heater is installed. The external water heater is provided with a gas-fired burner for heating water from the tank circulated in a heat exchanger to transfer heat from a fluid heated by the burner and circulated in the heat exchanger to transfer the heat to water circulated from the water tank.

Abstract: So as to provide a latent heat recovery-type water heater capable of certainly preventing drain generated by heat exchange from being discharged out of an exhaust portion through an outlet with entrained by a flow of combustion gas, an exhaust portion 9 is formed by an exhaust portion constituting-body 25 attached above a secondary heat exchanger 7. The exhaust portion 9 includes therewithin a deflector 26 and a distribution board 27 opposed to the deflector 26. The deflector 26 has a deflection board 30 extending substantially vertically downward from a top face 9a of the exhaust portion 9, so as to form a gap 35 between a lower end of the board 30 and a bottom face 9b of the exhaust portion 9. A flowing direction of combustion gas introduced into the exhaust portion 9 through an opening 21 of the bottom face 9b is deflected by passing through the gap 35, and the combustion gas flows toward the distribution board 27.

Abstract: A heat exchange apparatus of a high-load bottom-up-type condensing gas boiler is disclosed. In the gas boiler system having a ventilator attached to a lower part of a combustion chamber, the heat exchange apparatus structured in such a manner that a Venturi path for achieving a high-pressure and high-velocity flow of exhaust gas is mounted in an exhaust duct formed between a sensible heat exchanger in which first heat exchange is performed and a latent heat exchanger to which firstly heat-exchanged exhaust gas is flown, so that the sensible heat exchanger and the latent heat exchanger are perfectly independent from the exhaust gas after combustion.

Abstract: An apparatus for cooling a hot gaseous medium includes a vessel, wherein a bundle of pipes is disposed in a coolant compartment, and wherein a liquid coolant flows around the bundle. The pipes are mounted near upstream ends in a thermal shield and extend through openings in a support plate mounted at a distance from the thermal shield defining a front space between the thermal shield and the support plate in the vessel separated from the coolant compartment. The apparatus permits addition of liquid coolant to the front space. The openings in the support plate are larger than the pipes, defining an annular space. Liquid coolant flows co-current with the hot gaseous medium in the pipes from the front space to the coolant compartment. A skirt type extension surrounds the pipe in the front space to the support plate and having an opening at the thermal shield.

Abstract: A storage-type water heater includes a tank enclosing a volume of water, the tank having an upper portion and a lower portion, a chamber adjacent the lower portion of the tank and adapted to at least partially enclose a source of a heated fluid, and a helical tube heat exchanger at least partially enclosed within the tank and fluidly connected to the chamber. The helical tube directs the heated fluid from the lower portion to the upper portion of the tank and promotes heat exchange between the water in the tank and the heated fluid flowing therethrough.

Abstract: A gas water heater includes a water tank, a combustion chamber, a burner, a heat exchanger tube at least partially within the water tank, and a fan. The burner receives fuel gas and primary air to create a primary air-fuel mixture for combustion in the combustion chamber with secondary air. The primary air-fuel mixture has a gas concentration above the upper explosive limit of the fuel gas. Secondary air is supplied to the combustion chamber through a secondary air conduit that is separate from the burner. The heat exchanger tube receives the products of combustion, transfers heat from the products of combustion to water in the tank, and exhausts of the products of combustion. Only air flows through the fan; no fuel-air mixture flows through the fan. The water heater utilizes partial premix combustion with low excess air ratio and low contaminant emission.

Abstract: The invention relates to a boiler comprising a combustion chamber which is surrounded at least in part by a combustion gas flue that is embodied as a primary heat exchanger. The combustion gas flue is enclosed at least in part by a water-conducting housing while a water-conducting secondary heat exchanger that is hydraulically connected to the housing is mounted downstream of the combustion gas flue. According to the invention, the combustion chamber is surrounded at least in part by the secondary heat exchanger.

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 object is to provide a water heater capable of efficiently transmitting radiation heat of a burner to hot water in a hot water storage chamber with improved thermal efficiency. In the water heater, a second restriction part having a shallower depth than a first restriction part is arranged along a peripheral edge of a lower mirror plate of a hot water storage chamber with a protrusion part protruding in a ring shape toward the center side of the lower mirror plate. The protrusion part is further arranged between the first restriction part and the second restriction part, and a burner is positioned so that the burner combustion surface faces the protrusion part.

Abstract: A fuel-fired water heater includes a water storage tank, a flue positioned to receive combustion gases and transfer heat from combustion gases to water in the water storage tank, and a blower assembly. The blower assembly includes a housing defining an inlet positioned to receive combustion gases from the flue, an interior defined by the housing, and an outlet positioned to exhaust combustion gases from the interior of the housing. The blower assembly further includes a motor/impeller assembly that is positioned in the interior of the housing and is configured to direct combustion gases from the inlet of the housing toward the outlet of the housing. The housing of the blower assembly includes an interior wall portion, an exterior wall portion, and sound-absorbing material interposed between the interior and exterior wall portions. The interior wall portion defines perforations extending between the sound-absorbing material and the interior of the housing.

Abstract: A boiler includes a combustion chamber, a heat exchange section, and an outer housing. Coupling holes are formed in the outer housing, a circulation chamber is formed at a lower portion of the outer housing, and a burner is provided at an upper portion of the combustion chamber so as to generate heat in a downward direction thereof. The combustion chamber is vertically installed in one of the coupling holes, and a lower portion of the combustion chamber is communicated with the circulation chamber. The heat exchange section includes first and second heat exchangers and is vertically installed in the outer housing adjacent to the combustion chamber. An upper portion of the heat exchange section is coupled to one of the coupling holes and a lower portion of the heat exchange section is communicated with the circulation chamber.

Abstract: A device for preventing initial hot water from being discharged from a double pipe heat exchanger and a method of controlling the same, which can temporarily mix cold water with hot water so as to decrease the temperature of the discharged hot water when the high temperature water is initially discharged from the double pipe heat exchanger.

Abstract: A fluid heating apparatus for use in water heaters, boilers, cooking applications or the like comprising a body. The fluid heating apparatus also comprises a primary heat exchanger arranged within the body and a secondary heat exchanger arranged adjacent to the primary heat exchanger within the body. The apparatus also comprises a burner arranged within the primary heat exchanger. The primary heat exchanger comprises a plurality of concentric doughnut shaped plates arranged over the burner. A blocking plate is arranged adjacent to one of the concentric plates of the primary heat exchanger. The secondary heat exchanger comprises a plurality of concentric doughnut shaped plates arranged adjacent to the blocking plate on a side opposite of the plates of the primary heat exchanger. The apparatus further comprises a manifold in fluid communication with the plurality of concentric plates and blocking plates of both the secondary heat exchanger and primary heat exchanger.

Abstract: A coolant heater having a coolant tank and a burner tube within the coolant tank is used for marine and motor coach installations and is used for either a liquid powered or gas powered burner.

Abstract: A system and method for configuring a water heater to drain condensate from combustion products is provided. The water heater comprises a water tank, a burner for producing combustion products, a flue extending through an interior of the water tank to receive the combustion products, and an exhaust passageway positioned downstream of the flue and extending outside of the water tank to exhaust the combustion products. The exhaust passageway includes a first portion and a second portion positioned at an elevation above the first portion. A bypass conduit is coupled to the exhaust passageway and positioned to direct condensate in the exhaust passageway from the second portion toward the first portion. A drain port is positioned at or an elevation below the first portion of the exhaust passageway to drain condensate from the exhaust passageway.

Abstract: Disclosed herein is a once-through boiler capable of achieving a steep increase in temperature of steam via reheating of the steam within a combustion chamber, thereby improving heat and energy efficiency. The boiler comprises a body (110), a steam supply unit (120), and a heating unit (130). The body includes a housing (111), a cover (112), and a guide pipe (113). The steam supply unit includes an annular water tank (122) in a lower region of the body, a steam supply chamber (124) in an uppermost region of the body, water pipes (121) amounted on the water tank, a low-temperature steam inlet pipe (125) and a high-temperature steam outlet pipe (127) mounted at opposite sides of the water pipes, and a steam heating pipe (126) to communicate the inlet pipe with the outlet pipe. The heating unit includes a burner (131), and a combustion chamber (132).

Abstract: This exchanger comprises a pair of primary tubular bundles (5a, 5b) surrounding a fuel or gas burner (4a, 4b), and a secondary tubular bundle (6) on which condensation of the steam contained in the burned gases discharged from the primary bundles occurs, wherein the three bundles (5a, 5b, 6) are mounted parallel, side-by-side inside a gas-tight casing (10), and communicate with one another, with means being provided in order to circulate the water to be heated, between the tubes forming the secondary bundle (6) and the tubes forming the primary bundles (5a, 5b); the casing (10) is subdivided at the level of the secondary bundle (6) by a partition (7-70) that extends both inside and outside said bundle (6), with the arrangement being such that a only a circumferential section of the latter is capable of being contacted and traversed by the hot gases coming from one of the two primary bundles (5a), and its remaining section being capable of being contacted and traversed only by the hot gases coming from the oth

Abstract: A condensate trap for a condensing boiler has a generally hollow body for receiving condensate from a heat exchanger of the condensing boiler and for providing a path of flow for condensate out of the side of the boiler. The body of the condensate trap includes a condensate receiving end having an inlet, a condensate discharging end having an outlet, and an intermediate reversely-turned trap portion interconnecting the condensate receiving and discharging ends. The hollow body can be one-piece and molded of plastic. A level sensor can be mounted on or within the condensate receiving end of the body. In a preferred embodiment, the condensate receiving end includes a chamber with an opening, and the level sensor extends within the chamber and seals the opening. The condensate trap can also include an air vent located above the level sensor in communication with an air pressure sensor.

Abstract: A novel water heat exchanger with a helix coil incorporated into a stainless steel elongated variable diameter cylindrical housing. A buffer tank is incorporated within the lumen of the helix coil. In one embodiment, the heat exchanger utilizes a radial direct-firing burner and a blower-driven hot flue gas to heat water for domestic and commercial use. In one embodiment, at least a rope seal is disposed between adjacent coil loops of a portion of the helix coil for enhancing heat transfer to the helix coil. In one embodiment, solar and electric heating systems are combined with the helix coil heat exchanger and disposed within the buffer tank to provide supplemental heating. In another embodiment, the heat exchanger further comprises a Stirling engine comprised of a free piston having hot and cold ends that is disposed within the cavity taken up the buffer tank, wherein the hot end receives heat from the burner and the cold end is cooled by the incoming cold water line to form an electric power generator.

Abstract: A forward combustion type condensing gas water heater is provided including a burner, a primary heat exchanger, a drain pipe for condensation water, a gathering and discharge device for condensation water, a secondary heat exchanger. The gathering and discharge device and the secondary heat exchanger have center lines different from the primary heat exchanger. Flue gas rises through the primary heat exchanger and passes through the secondary heat exchanger in a direction staggered with respect to the falling direction of condensation water. The condensing gas water heater effectively avoids resistance between the condensation water and the flue gas and prevents the condensation water from flowing to the burner, the combustion chamber, and the ignition pin.

Abstract: A fuel reformer burner for a polymer electrolyte membrane fuel cell (PEMFC) system includes a first tube through which a fuel for a fuel reformer is supplied and a second tube through which anode-off gas (AOG) is supplied from a fuel cell stack. The second tube is not connected to the first tube, and an inlet line through which an air is supplied is connected to the first tube.

Abstract: A domestic heating fuel composition, comprising (a) a paraffinic hydrocarbon composition comprising at least 90 wt % normal paraffins and/or iso-paraffins comprising from 6 to 24 carbon atoms, wherein the weight ratio of iso-paraffins to normal-paraffins is below 6 to 1, and (b) at least one compound having a C/H molar ratio of above 0.8 and soluble in component (a) at ambient conditions, wherein the component (b) is present in the fuel composition in an amount effective to increase the responsiveness of a yellow/red flame detector to a required threshold level.

Abstract: There is described a boiler (1) including a burner (3), a heat exchanger (50) adapted to raise the temperature of a working fluid through heat exchange with an exchange fluid, including a plurality of heat exchanger modules (2) placed side by side in order to define a combustion chamber within which the burner (3) for the generation of exchange fluid is inserted, exchange walls (2C) for the passage of exchange fluid, an expulsion chamber (2D) for the exchange fluid fitted with a discharge flue (4) and a substantially parallelepiped casing (5) adapted to be filled with working fluid. The boiler includes side walls (5D) inter-connected by stay-plates (6) placed between the heat exchanger modules (2) and top and bottom walls (5B) and end walls (5C) fitted with reinforcing elements (8) which prevent their deformation due to the pressure of working fluid.

Abstract: A water heater has a burner positioned below a vertical centrally located flue with heat exchange capacity enhanced by a multiplicity of rectangular metal fins which are welded on the inside of the vertical central flue. The central flue extends upwardly within a water tank. The central flue transitions to a smaller diameter downwardly draining helically coiled condensing flue. Approximately 80% of the heat from the combustion gases is transferred to the water within the water tank through the wall of the central flue without condensation. An additional 10% or more of the combustion heat is transferred to the water accompanied by condensation of water in the coiled flue. A fan draws the combustion gases through the central flue and the coiled condensing flue and supplies the combustion gases to an exterior vent.

Abstract: A heat exchanger for a boiler comprises a central chamber for receiving a combustion gas. A baffle divides the central chamber into a first section and a second section. The baffle also restricts the combustion gas from flowing directly from the first section of the central chamber to the second section of the central chamber. There is a plurality of spaced-apart flues disposed about a periphery of the central chamber. The flues allow for communication between the first section of the central chamber and the second section of the central chamber, in particular, the flues allow for combustion gas to flow from the first section of the central chamber to the second sections of the central chamber.

Abstract: The present invention discloses a heat transfer unit which integrates a boiler and a gas preheater for steam generation and gas preheating. In one embodiment, the heat transfer unit of the present invention may be used in fuel processing applications. In this embodiment, the heat transfer unit may be located downstream of a combustor such as an anode tailgas oxidizer.

Abstract: The present invention provides a new heat exchanger element comprising a premix burner with an outward curved or ridged burner surface. The heat exchanger element further comprises a combustion chamber. The combustion chamber is bound on one side by the burner and is further made up of water cooled metal walls which, starting from the burner and in downstream direction, first widen and thereafter narrow down to the width of a customary heat exchanger element. This creates enough space for a proper combustion, avoiding dead angles and recirculation or too early ending of the combustion reaction, thereby reaching low emissions of NOx and CO.

Abstract: Provided is a combustion apparatus that can positively prevent a combustible gas present in the vicinity from catching fire in performing prepurge, which involves exhausting air from a combustion chamber provided with a burner, before igniting the burner. The combustion apparatus 1 contains combustion control means 6 that ignites the burner after performing prepurge by use of a fan 4, and gas detection means 5 that is provided between an air supply port 7 and the fan 4 and detects the concentration of a combustible gas. The combustion control means 6 ascertains, before starting the prepurge, whether a combustible gas of a preset maximum concentration or higher is detected by use of the gas detection means 5 (STEP 1) and prohibits the prepurge by prohibiting the energization of the fan 4 when a combustible gas of the maximum concentration or higher has been detected (STEP 2).

Abstract: A steam boiler (15) comprising a fuel burning device (16) disposed in a combustion chamber and adapted to burn a fuel to form combustion gases (19), a passage (30) extending between a water inlet (20) and a steam outlet (23), the passage having a water space (31) and a steam space (32), a flue passage (33) extending between the combustion chamber and a flue outlet (24) and having a gas heat transfer space (34), a heat exchange element (43) between the gas heat transfer space and the water and steam spaces, the heat exchange element having a gas-side surface (35) that absorbs heat from the combustion gases and an opposed water-side surface (38) that radiates heat, the water-side surface having a first portion (39) adjacent to the water space and a second portion (40) adjacent to the steam space, the gas-side surface having a first portion (36) opposite the water-side first portion and a second portion (37) opposite the water-side second portion, the water-side first portion having a surface area and the water

Abstract: A water heater for heating water includes a burner assembly (54) for generating a flow of hot gas. The burner assembly (54) includes a gas burner (52) and means (64) adjustable to determine a heat output of the burner assembly (54). The water heater further includes a heat exchanger assembly (20) for transferring heat from gas to water flowing therein. The heat exchanger assembly (20) has a higher temperature zone (110) and a lower temperature zone (100). The water heater is arranged to convey the flow of hot gas to the higher temperature zone (110) and in turn to the lower temperature zone (100).

Abstract: A heat apparatus (1), in particular for providing heating in a space, such as central heating, or for heating tap water in, for instance a boiler, comprising: a burner; provided with a guide channel for air supply and/or flue gas discharge; wherein in the guide channel a sound reflecting structure (10) is included extending transversely relative to the guide channel, and designed for damping a sound caused by the burner by means of sound reflection.

Abstract: A method and apparatus for maintaining a relatively constant temperature of a working fluid in an evaporator of a refrigeration system by providing a constant volumetric displacement compressor and a heat exchanger for exchanging heat between the high pressure and low pressure portions of a refrigeration circuit to superheat, and hold substantially constant, the temperature of the refrigerant entering the compressor. In doing this, the pressure of the refrigerant in the low pressure portion of the circuit, including the evaporator, and the mass flow rate of the refrigerant remain substantially constant. As a result, the temperature of the saturated refrigerant in the evaporator remains substantially constant.

Abstract: A storage type water heater comprising: a stored hot water tank; a heating unit including a heat exchanger, a gas burner, and an air supply fan; a circulation pipe line; a circulating pump; a first temperature sensor for detecting an inlet side temperature T1; a second temperature sensor for detecting an outlet side temperature T2; and a controller including a control arrangement which actuates the circulating pump to circulate the stored hot water inside of the circulation pipe line when the heating unit is in a non-operated state, and determines an abnormality in one of the first temperature sensor and the second temperature sensor based on a temperature difference (|T1?T2|).

Abstract: A water heating apparatus uses a low range blower assembly and a high range blower assembly, each providing a variable flow of premixed fuel and air to a burner assembly. Appropriate choice of the operating ranges of the blower assemblies can provide a high turndown ratio approximately equal to the product of the turndown ratios of each of the individual blower assemblies. Turndown ratios as high as 25:1 are achievable.

Abstract: A gas water heater includes a power burner, a flue tube, an exhaust plenum, and a draft hood. The flue tube includes a portion that describes at least a 360° loop. Products of combustion are forced through the flue tube under the influence of the power burner, and enter the exhaust plenum. In the exhaust plenum, the pressure of the products of combustion drops such that the products of combustion flow into the draft hood substantially entirely under the influence of natural convection. In one embodiment, the power burner fires down into the flue tube through a side wall of the water heater, the loop of the flue tube is near the bottom of the water heater, and the plenum is in the top of the water heater.

Abstract: A heating system for heating a fluid, the system comprising two separate heat exchangers, each directly heated by a burner to heat the fluid, a common flue into which the two burners are arranged to discharge their exhaust gas, a common fan arranged to supply air to the two burners, and a gas supply to each burner. A splitter valve splits the air flow from the fan to the two burners. A controller controls the speed of the fan, the position of the splitter valve and the gas supplies according to the heat output requirement of the system.

Abstract: A method of manufacturing a combustion chamber for use in a water heater is provided. A skirt is formed, and an edge portion of a plate is spot welded to the skirt. The edge portion of the plate is circumferentially welded to the skirt, thereby forming a seal between the plate and the skirt.

Abstract: A method of manufacturing a combustion chamber for use in a water heater is provided. A skirt is formed, and an edge portion of a plate is spot welded to the skirt. The edge portion of the plate is circumferentially welded to the skirt, thereby forming a seal between the plate and the skirt.

Abstract: A portable tankless water heater includes a heat exchanger disposed in a sealed housing with an inlet cold water line and an outlet hot water line extending outside the sealed housing. A burner, disposed in an operative relationship with said heat exchanger is provided for heating water flowing through said heat exchanger and an exhaust system induces draft of air from a housing air inlet through said heat exchanger and out of a housing flue outlet.

Abstract: An application for a method of heating water includes transferring the water from a water supply into an inner tank of the water heater which is held within an outer tank, transferring the water from the inner tank into an outer tank and then to supply a building with hot water. The water in the outer tank is heated with hot gasses, partially cooling to intermediate temperature gasses. The water in the inner tank is heated with the intermediate temperature gasses, further cooling the intermediate temperature gasses into cooler gasses that are then exhausted out of the water heater.

Abstract: A heat exchanger, provided with a body with at least one flue gas channel and at least one water carrying channel, at least one burner space and at least one flue gas discharge, wherein the at least one flue gas channel extends at least partly between at least a burner space and at least one flue gas discharge and at least a portion of the at least one flue gas channel comprises at least one porous or gas-transmissive heat exchange element.

Abstract: An apparatus for cooling hot gas comprises: (i) a vertical elongated vessel provided with a cooling medium compartment comprising in use a first cooling medium, an inlet to supply fresh first cooling medium and a outlet for discharge of used first cooling medium, the vessel further provided with an inlet for hot gas and an outlet for cooled gas, at least one heat exchange tube, which heat exchange tube is positioned in the cooling medium compartment (and fluidly connects the inlet for hot gas and the outlet for cooled gas, (ii) said cooling medium compartment further comprising a vertical and centrally positioned open ended downcomer wherein said heat exchange tube is positioned in a space between the downcomer and the vessel wall, (iii) and wherein the heat exchanger tube is mounted at its upstream end in a tube plate and wherein the tube plate is provided with means to supply a second cooling medium to the exterior of the upstream end of the heat exchanger tube, means to discharge the used second cooling m

Abstract: The invention relates to a condensation heat exchanger. The inventive heat exchanger consists of two co-axial helicoidal tube bundles which are positioned end-to-end, one of said bundles (2a) serving as a primary exchanger and the other (2b) serving as a secondary exchanger. Each of the aforementioned bundles comprises a tube and/or a group of flat tubes which are mounted inside a gas-impermeable casing (1). Moreover, means are provided to circulate at least one fluid to he heated inside the tubes, the casing (1) being equipped with a gas exhaust sleeve (122). In this way, a first hot gas, known as the main gas, which is, for example, generated by a burner (6), passes radially through the voids in the bundles. A deflector system (7) ensures that said main hot gas first passes through the primary exchanger (2a) from inside outwards and, subsequently, the secondary exchanger (2b) from outside inwards, after which it is discharged from the exchanger through the above-mentioned sleeve (122).

Abstract: An application for a method of heating water includes burning fuel to produce hot gases and heating a first mass of water with a first heat exchanger coupled to the hot gases. Heat remaining after the hot gases pass through the first heat exchanger is used by a second heat exchanger to heat a second mass of water. The first mass of water is partially isolated from the second mass of water and the first mass of water is contained substantially within the second mass of water. The second mass of water is colder than the first mass of water and, thereby, condenses more water vapor out of the hot gases.

Abstract: There is provided a circulation type hot water supply device in which a downstream end of a hot water delivering channel 6 connected to a heat exchanger 4 of a water heater 1 is connected to a water supply channel 5 upstream of the heat exchanger, and a circulating pump 25 that returns hot water fed from the heat exchanger to the hot water delivering channel to the heat exchanger through the water supply channel is provided in the hot water delivering channel. The device can reliably identify an abnormality when it occurs, such as adhesion of a deposit to an inner surface of a heat absorbing pipe 4b to reduce heat exchange efficiency. A diagnosis is started when a hot water delivering tap 7 is closed and a burner 3 is subjected to combustion. In the diagnosis, supply of water to the heat exchanger 4 is first stopped to shut down the burner 3.

Abstract: A condensate trap for a condensing boiler has a generally hollow body for receiving condensate from a heat exchanger of the condensing boiler and for providing a path of flow for condensate out of the side of the boiler. The body of the condensate trap includes a condensate receiving end having an inlet, a condensate discharging end having an outlet, and an intermediate reversely-turned trap portion interconnecting the condensate receiving and discharging ends. The hollow body can be one-piece and molded of plastic. A level sensor can be mounted on or within the condensate receiving end of the body. In a preferred embodiment, the condensate receiving end includes a chamber with an opening, and the level sensor extends within the chamber and seals the opening. The condensate trap can also include an air vent located above the level sensor in communication with an air pressure sensor.

Abstract: A flue system is provided for a water heater having improved heat exchange efficiency. The flue system includes an upstream heat exchange portion having at least one substantially vertical flue tube. The flue system also includes a downstream heat exchange portion having at least one substantially vertical flue tube. The upstream heat exchange portion provides a first pass for heat exchange with water in a water heater. The downstream heat exchange portion provides a second pass for heat exchange with water in the water heater.