Abstract: A water heater comprising a closed tank having a water inlet for connection with a water supply, and a hot water outlet connected to the tank interior; a flue pipe extending vertically through the tank and having an upper portion for connection with a vent pipe; a cylinder having a lower end and upper open end with means for opening disposed within the flue pipe, and spaced from inner walls of the flue pipe, and extending substantially the length of the flue pipe; a burner disposed in a lower region of the cylinder, such that combustion products from the burner rise through the cylinder; and a water conducing coil disposed within the cylinder connected with the interior of the tank.

Abstract: A water heater comprising a closed tank having a water inlet for connection with a water supply, and a hot water outlet connected to the tank interior; a flue pipe extending vertically through the tank and having an upper portion for connection with a vent pipe; a cylinder having a lower end and upper open end with means for opening disposed within the flue pipe, and spaced from inner walls of the flue pipe, and extending substantially the length of the flue pipe; a burner disposed in a lower region of the cylinder and above the lower end thereof, such that combustion products from the burner rise through the cylinder; and a water conducing coil disposed within the cylinder connected with the interior of the tank.