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 high-efficiency hot-water boiler for a heating system of a building is provided. The boiler includes a boiler enclosure that contains a furnace area compartment within an insulated sealed casing, a first watertube compartment within a sealed casing, a second watertube compartment within a sealed casing, and an air-to-air preheat exchanger within a sealed casing. A plurality of separate, closely-spaced watertubes extends within each of the compartments and provides paths for working fluid to flow through the compartments for purposes of transferring heat to the working fluid. A burner is located within the furnace area compartment for combusting an air/gas mixture.

Abstract: A boiler is provided that has an elongate base header, an elongate dome header, and a plurality of separate watertubes each having an intermediate section and opposite end sections. An upper one of the end sections of each watertube is connected to the dome header and a lower one of the end sections of each watertube is connected to the base header such that the intermediate section extends through a combustion chamber of the boiler. The intermediate section of each watertube has a substantially constant outer diameter along its full length and is closely spaced to adjacent watertubes within the combustion chamber. At least one of the end sections of each watertube has a transition that reduces the diameter of the watertube as it extends from the intermediate section to an outwardly-extending circumferential flange. This arrangement permits close spacing of the connection sites of the watertubes to the header and permits the connection sites to be provided in a linear array.

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 one-piece tube for use as a watertube within a watertube boiler or heat exchanger has a free end section that is formed to have an integral, outward-extending circumferential ring, or flange, a spaced distance from an adjacent end face of the tube. This is preferably accomplished by radially expanding the tube within the free end section and by axially compressing the free end section to cause a portion of the tube to bulge radially outward to from the circumferential ring, or flange. The flange enables the watertube to be readily driven into engagement with a dome, manifold or like casting without the creation of leaks, such as weld leaks. The free end section of the tube that extends from the circumferential ring, or flange, to the adjacent end face of the tube can be formed with a taper such that the diameter of an outer wall of the tube progressively decreases from the circumferential ring, or flange, to the end face.

Abstract: A flue-gas to air heat exchanger having a flue-gas containing shell with a heat exchange surface, flue-gas inlet and outlet sections, and at least one tubular clean-out fitting is provided with a removable plug having an outer peripheral portion resiliently engageable with a section of the inner peripheral portion of the fitting adjacent the shell. The plug periphery is expanded into gas-tight sealing contact with the fitting inner periphery by means affording installation and removal without tools.