tefal express steam generator iron not working?

My tefal gv8330 only generates steam for about 5/10 minutes and then stops. the iron is ok to dry iron. The cable carrying the steam to the iron cools down when it stops producing steam. The burring sound from the generator is still heard as it does when it works ok. and the thermostat light on the iron comes on and off as it usually does intermittently. No leaks anywhere. Anyone any idea what part might need replaced...where I get it from etc?

Moira
December 2014