Abstract: A steam producing device is operative to discharge high velocity steam for use in steam cleaning and includes a burner positioned within a housing and supplying heat to a plurality of generally coaxial, fluid containing coils including a warming coil, a closely wound wall cooling or intermediate coil, a preheat coil and a final heat coil. The warming coil is located within the wall cooling coil and discharges thereinto near the upper end of the housing. The wall cooling coil discharges near burner level into the preheat coil which conically decreases in diameter toward the upper end of the housing where it connects to the final heat coil. The final heat coil descends toward the burner and terminates in connection with a nozzle bearing discharge hose.