I have provided a link to a manual that seems to belong to your model. But unsure what features your model has. This is not available for some reason at the Rowenta USA website.
Refer page 7 of the manual available at this site
http://laundry.manualsonline.com/manuals/mfg/rowenta/1103898336__4605.html?p=1

Self Clean - prolongs the life of the iron
The Self clean function flushes dirt and scale particles
out of the steam chamber.
To operate:
• Fill the tank with untreated tap water up to the maximum
mark and heat the iron to max. temperature.
• Unplug from the mains.
• Hold iron over a sink horizontally, push the steam control
3 past the position and into the Self Clean position
and hold it there: steam will now begin to build up.
After a few seconds water and steam will emerge from
the soleplate, rinsing dirt and scale particles out of the
steam chamber.

After approx. 1 minute move the steam control slide to
the position.
• Insert mains plug and allow the iron to heat up again.
• Wait until the remaining water has evaporated.
• Unplug from the mains and allow iron to fully cool
down.
• When cool, the soleplate can be wiped with a damp
cloth.
We recommend using the Self Clean function approx.
Every 2 weeks. If the water is very hard, the iron should
be cleaned weekly.
Self Clean Valve
The self clean valve prevents the drip hole into the steam
chamber from furring or blocking up. To ensure the iron
continues to function properly, open and close the valve
by sliding the steam control to max then min a few times
after use.