Have the same problem continuously streams. It has to be valve that releases the steam.
Is the valve on the tank or in the iron, would think the valve is on the tank as I don't think the pipes are pressurised.
If the micro switch is broken then the valve should shut when the power is off, BUT on mine you can fill the tank and lower iron and the water flows through and out of the Iron.
My thoughts are value is stuck open by scale or is just broken.
Now to find the valve.
Simon
February 2009