The disclosure provides a collective exhaust system capable of safely detecting a closing failure of a check valve of the collective exhaust system. The collective exhaust system includes: multiple combustion devices including blowing parts and exhaust pipes; a collective exhaust duct to which the exhaust pipes of the multiple combustion devices are respectively connected; and check valves respectively provided between the exhaust pipes and the collective exhaust duct. The collective exhaust system is configured to detect a closing failure of the check valves by performing, in a state where one of the blowing parts of the multiple combustion devices is stopped and all the other blowing parts are driven with a predetermined blower capacity, a backflow determination from the collective exhaust duct to the combustion device with the stopped blowing part, and by performing the backflow determination for the multiple combustion devices.

Disclosed is a water heater including a case provided with an air supply hole and an air discharge hole, a burner provided in an interior of the case, and a humidified air supply part that provides humidified air to the burner together with a fuel. The humidified air supply part includes a first accommodation tank that accommodates water to generate vapor, and a humidified air supply tank that provides a space for supplying the vapor supplied from the first accommodation tank to air introduced into an interior of the case through the air supply hole.

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 system for a forced air flow into a kamado-style cooker comprises a control unit and an adapter defining an airflow duct with an entrance aperture and an exit aperture. The adapter is configured to removably mount over a lower damper port in a kamado-style cooker such that the exit aperture is aligned with the lower damper port. The control unit comprises an electric fan, one or more sensor input ports, and an airflow exit duct. The control unit is configured to separably mate with the adapter such that the airflow exit duct of the control unit is received by the entrance aperture of the adapter. Advantageously, a forced air flow generated by the electric fan, in response to a temperature signal input, passes out of the control unit, through the adapter, and into a body portion of the kamado-style cooker to encourage, facilitate and manage combustion within the cooker.