My G1129STsteamworks iron is not letting the steam through ?

Only bought the iron a month ago and unfortunately have thrown out the box with instructions . The iron heats up but no steam is coming through so the water tray never empties. I presumed it was the filter, and so replaced it but there is no improvement. When I press the steam button there is no noise ,as there was when it was working. As it unlikely I can replace without original packaging or receipt, does anyone have any ideas ???