Abstract: The invention includes a warewasher comprising a wash chamber, a tank at the bottom of said chamber for supplying recirculated heated water through a pump to wash arms in said chamber, a primary water heating system comprising a heat exchange tube entering said tank through a first port or inlet in said tank, traversing the base of the tank, and exiting said tank through a second port or outlet, said tube being at a height in said tank such that the tube is submerged when said tank is filled with water, said tube having a first end and a second end located outside of the tank and providing a passageway between the ends, a gas-fired infrared burner located in said tube adjacent said first end to which an air/gas mixture is supplied and combusted by said burner, at least one secondary labyrinthine heat exchanger in intimate heat transfer relationship with at least one of the walls of said tank below the water level, and controls for automatically operating the heating system in response to a need to increase th

Abstract: The invention includes a warewasher comprising a wash chamber, a tank at the bottom of said chamber for supplying recirculated heated water through a pump to wash arms in said chamber, a primary water heating system comprising a heat exchange tube entering said tank through a first port or inlet in said tank, traversing the base of the tank, and exiting said tank through a second port or outlet, said tube being at a height in said tank such that the tube is submerged when said tank is filled with water, said tube having a first end and a second end located outside of the tank and providing a passageway between the ends, a gas-fired infrared burner located in said tube adjacent said first end to which an air/gas mixture is supplied and combusted by said burner, at least one secondary labyrinthine heat exchanger in intimate heat transfer relationship with at least one of the walls of said tank below the water level, and controls for automatically operating the heating system in response to a need to increase th

Abstract: The invention is a warewasher comprising a wash chamber, a tank at the bottom of the wash chamber, a heat exchange tube entering the tank through a first port in the tank, traversing the base of the tank, and exiting the tank through a second port. The tube is at a height such that it is submerged when the tank is filled with water. The tube has first and second ends outside the tank, and a gas-fired infrared burner located in the tube adjacent the first end to which a combustible fuel is supplied and combusted by the burner. The combustion products of the fuel are received in the tube and are vented at the second end. By combusting fuel and passing the combustion products through the tube, water in the tank is heated.