The most likely cause is a defective heating element .
You will have trouble finding a replacement element and you will have trouble finding an electrician willing to do the work.
Even if you could find the part you require the total cost of repair will probably be more than a new machine.
Give up - throw it away and buy a new one - the VAX steam cleaners are popular - Amazon £44 to £100
Good Luck..., August 2015
