Try the Rowenta web site at: http://www.rowenta.com/rowenta/frame.aspx?page=http://www.rowenta.com/rowenta/All+products/Kitchen+appliance/Espressos/Products/PRELUDE/PRELUDE+Espresso+machine+-+Main+features.htm
They have a similar model - the Allegro, but if that doesn't help you may want to contact them. I was able to figure it out quite easily by trial and error.
Gerald
November 2008