A flue damper may include a flue pipe with a first side leading to an outlet of the flue damper and a second side leading to an inlet of the flue damper. A damper gate may be included and have an open state and a closed state, where in the open state, the first side of the flue pipe is in fluid communication with the second side, and where in the closed state, the damper gate interrupts fluid communication between the first side and the second side. A float may be secured to an upper surface of the damper gate. The upper surface of the damper gate may face the first side of the flue pipe when the damper gate is in the closed state such that the damper gate at least partially opens when condensate collects within the first side of the flue pipe.

An apparatus for removing moisture from exhaust gas is disclosed. The apparatus includes an inner chamber including an inner exhaust port, configured to discharge the exhaust gas flowing along a chimney, and an outer chamber, surrounding the inner chamber and including an outer exhaust port configured to discharge the exhaust gas discharged from the inner exhaust port, wherein an exhaust path is defined between the inner chamber and the outer chamber such that the exhaust gas discharged from the inner exhaust port flows along the exhaust path and is discharged through the outer exhaust port.

An end fitting for an exhaust pipe includes a cylindrical body having an upper opening and a lower opening. An inclined upper board is mounted in the cylindrical body. An upper passage is defined between a side of the upper board and an inner periphery of the cylindrical body. A first set of drain holes is defined in the lowest portion of the upper board. An inclined lower board is mounted in the cylindrical body and is located below the upper board. A lower passage is defined between a side of the lower board and the inner periphery of the cylindrical body. The lowest portion of the lower board is connected to the cylindrical body. The cylindrical body includes a cylindrical wall having a second set of drain holes. A ledge extends from the inner periphery of the cylindrical body and is located below the lower board.

An end fitting for an exhaust pipe includes a cylindrical body having an upper opening and a lower opening. An inclined upper board is mounted in the cylindrical body. An upper passage is defined between a side of the upper board and an inner periphery of the cylindrical body. A first set of drain holes is defined in the lowest portion of the upper board. An inclined lower board is mounted in the cylindrical body and is located below the upper board. A lower passage is defined between a side of the lower board and the inner periphery of the cylindrical body. The lowest portion of the lower board is connected to the cylindrical body. The cylindrical body includes a cylindrical wall having a second set of drain holes. A ledge extends from the inner periphery of the cylindrical body and is located below the lower board.

A nozzle assembly for a fan unit includes an inner nozzle having a tapered outer diameter and a flow path radially inward from the tapered outer diameter with respect to a longitudinal axis of the nozzle assembly. The flow path is configured to guide a fluid flow and to expel the fluid flow through an inner outlet of the inner nozzle to a surrounding environment. The nozzle assembly also includes an outer nozzle disposed radially outward from the inner nozzle with respect to the longitudinal axis. The outer nozzle and the tapered outer diameter of the inner nozzle define an annular flow path therebetween. The annular flow path is configured to guide the fluid flow and to expel the fluid flow to the surrounding environment through an outer outlet of the outer nozzle. A cross-sectional area of the outer outlet is adjustable via movement of the inner nozzle, the outer nozzle, or both along the longitudinal axis of the nozzle assembly.

A flue damper may include a vent pipe with a first side leading to an outlet of the flue damper and a second side leading to an inlet of the flue damper. A damper gate of the flue damper may be movable between an open state and a closed state, where in the open state, the first side of the vent pipe is in fluid communication with the second side, and where in the closed state, the damper gate interrupts fluid communication between the first side and the second side. A drainage port may also be included, and a plug may be movable relative to the drainage port to selectively seal the drainage port when the damper gate remains in the closed state.

A flue damper may include a vent pipe with a first side leading to an outlet of the flue damper and a second side leading to an inlet of the flue damper. A damper gate of the flue damper may be movable between an open state and a closed state, where in the open state, the first side of the vent pipe is in fluid communication with the second side, and where in the closed state, the damper gate interrupts fluid communication between the first side and the second side. A drainage port may also be included, and a plug may be movable relative to the drainage port to selectively seal the drainage port when the damper gate remains in the closed state.

A nozzle assembly for a fan unit includes an inner nozzle having a tapered outer diameter and a flow path radially inward from the tapered outer diameter with respect to a longitudinal axis of the nozzle assembly. The flow path is configured to guide a fluid flow and to expel the fluid flow through an inner outlet of the inner nozzle to a surrounding environment. The nozzle assembly also includes an outer nozzle disposed radially outward from the inner nozzle with respect to the longitudinal axis. The outer nozzle and the tapered outer diameter of the inner nozzle define an annular flow path therebetween. The annular flow path is configured to guide the fluid flow and to expel the fluid flow to the surrounding environment through an outer outlet of the outer nozzle. A cross-sectional area of the outer outlet is adjustable via movement of the inner nozzle, the outer nozzle, or both along the longitudinal axis of the nozzle assembly.

A nozzle assembly for a fan unit includes an inner nozzle having a tapered outer diameter and a flow path radially inward from the tapered outer diameter with respect to a longitudinal axis of the nozzle assembly. The flow path is configured to guide a fluid flow and to expel the fluid flow through an inner outlet of the inner nozzle to a surrounding environment. The nozzle assembly also includes an outer nozzle disposed radially outward from the inner nozzle with respect to the longitudinal axis. The outer nozzle and the tapered outer diameter of the inner nozzle define an annular flow path therebetween. The annular flow path is configured to guide the fluid flow and to expel the fluid flow to the surrounding environment through an outer outlet of the outer nozzle. A cross-sectional area of the outer outlet is adjustable via movement of the inner nozzle, the outer nozzle, or both along the longitudinal axis of the nozzle assembly.

An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a bearing chamber and surrounding annular space. A fan driven by a shaft extending downward from the bearing chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly.