The air-fuel mixture permeable member is disposed to overlap that surface of the burner frame which lies opposite to the burner body. The fixing frame is disposed so as to be fixed to the inner peripheral portion of the enclosing frame part of the burner frame by pinching the air-fuel mixture permeable member between the inner peripheral portion and the fixing frame. The air-fuel mixture permeable member has an extended part protruding outward beyond the fixing frame so as to cover by this extended part an outer peripheral portion of the enclosing frame part.

The air-fuel mixture permeable member is disposed to overlap that surface of the burner frame which lies opposite to the burner body. The fixing frame is disposed so as to be fixed to the inner peripheral portion of the enclosing frame part of the burner frame by pinching the air-fuel mixture permeable member between the inner peripheral portion and the fixing frame. The air-fuel mixture permeable member has an extended part protruding outward beyond the fixing frame so as to cover by this extended part an outer peripheral portion of the enclosing frame part.

The disclosed technology includes a combustion system providing ease of access to components of the combustion system and optimal placement of a burner such that efficient combustion and heat transfer can occur. The combustion system can include an inner tube having a first end and a second end, the second end having a flange with a sensor port, and an outer tube having a first end and a second end. The inner tube can be disposed within the outer tube. The inner tube can have an outer diameter less than an inner diameter of the outer tube, creating a gap between the outer tube and inner tube. An ignitor assembly and a flame sensor assembly can extend through the sensor port and the gap and be positioned proximate a burner.

The disclosed technology includes a water heater system having a blower, an igniter, a burner, a heat exchanger, and a refractory configured to attach to the burner and the heat exchanger. The refractory can include a unitary ceramic housing having a top and a plurality of sidewalls and be configured to retain heat from combustion gases. The top can have a burner aperture configured to receive at least a portion of the burner and the plurality of sidewalls can form a cavity configured to receive at least a portion of the heat exchanger. One or more of the sidewalls can additionally have a protrusion extending laterally along an inside surface of the sidewall that is configured to contact the heat exchanger to form a seal between the heat exchanger and the refractory. A sealing material can substantially create a seal between the refractory and the heat exchanger.

The disclosed technology includes a water heater system having a blower, an igniter, a burner, a heat exchanger, and a refractory configured to attach to the burner and the heat exchanger. The refractory can include a unitary ceramic housing having a top and a plurality of sidewalls and be configured to retain heat from combustion gases. The top can have a burner aperture configured to receive at least a portion of the burner and the plurality of sidewalls can form a cavity configured to receive at least a portion of the heat exchanger. One or more of the sidewalls can additionally have a protrusion extending laterally along an inside surface of the sidewall that is configured to contact the heat exchanger to form a seal between the heat exchanger and the refractory. A sealing material can substantially create a seal between the refractory and the heat exchanger.

An air and gas feeder device for gas boilers, comprising an air-gas conveyance body which comprises: a boiler coupling face configured to be coupled to a boiler at an intake duct of the boiler; an air intake port connected to an air discharge opening by means of an air passage, the air discharge opening leading out from the boiler coupling face; a gas intake port, configured to be fixed to a gas dispensing duct in fluid communication with a gas discharge opening, which leads out from the boiler coupling face; wherein the air discharge opening is coaxial to, and at least partially surrounded by, the gas discharge opening; the air passage accommodates a flow diverter configured to divert an air flow in output from the air discharge opening in the direction of the gas in output from the gas discharge opening and to impart a rotation to said air flow.

A fresh-air intake according to aspects of the disclosure includes an outer cover having a pair of side panels disposed in a generally parallel spaced relationship, a top panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels, a bottom panel disposed generally parallel to the top panel, and a front panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels and the top panel, the front panel having a window formed therein, a supply line coupled to the bottom panel, a weir extending above the bottom panel and surrounding a junction with the supply line, a baffle disposed inside the outer cover, the baffle being disposed inwardly of the window so as to prevent infiltration of moisture into the supply line, and a weep hole formed in the bottom panel.

A fresh-air intake according to aspects of the disclosure includes an outer cover having a pair of side panels disposed in a generally parallel spaced relationship, a top panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels, a bottom panel disposed generally parallel to the top panel, and a front panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels and the top panel, the front panel having a window formed therein, a supply line coupled to the bottom panel, a weir extending above the bottom panel and surrounding a junction with the supply line, a baffle disposed inside the outer cover, the baffle being disposed inwardly of the window so as to prevent infiltration of moisture into the supply line, and a weep hole formed in the bottom panel.

A forced-draft pre-mix burner device has a housing that conveys air from an upstream cool air inlet to a downstream warm air outlet. A heat exchanger warms the air prior to discharge via the warm air outlet. A gas burner burns an air-gas mixture to thereby warm the heat exchanger. A fan mixes the air-gas mixture and forces the air-gas mixture into the gas burner. The fan has a plurality of blades having sinusoidal-modulated blade spacing.

A forced-draft pre-mix burner device has a housing that conveys air from an upstream cool air inlet to a downstream warm air outlet. A heat exchanger warms the air prior to discharge via the warm air outlet. A gas burner burns an air-gas mixture to thereby warm the heat exchanger. A fan mixes the air-gas mixture and forces the air-gas mixture into the gas burner. The fan has a plurality of blades having sinusoidal-modulated blade spacing.