a controlled manner the free or distal end of the shaft member corresponds to the second valve operating region and includes a thin blade shaped member 13 to allow maximum flow of water from the reservoir 3 to the steam chamber in the self cleaning mode the near end of the elongated shaft or piston member 11 is connected to a valve controller the other end the distal end of the shaft is free and can be moved by the valve controller towards and away from an outlet nozzle 31 which is an aperture separating the reservoir and the steam generating chamber to form a valve having a variable aperture size the elongated shaft member 11 is received within a through cylindrical well 32 which is formed through the reservoir in a direction substantially normal to the plane of the reservoir housing 3 and that of the soleplate 4 at the base of the cylindrical well an slotted outlet nozzle 31 is provided this outlet nozzle permits water in the reservoir to flow under gravity from the reservoir into the steam chamber unless blocked with this arrangement the reservoir is communicable with the steam chamber through the outlet nozzle and the extent of communication between the reservoir and the steam chamber is controllable by the instantaneous aperture formed between the nozzle 31 and the shaft member 11 the shaft or piston member 11 generally includes a first and a second valve operating.