Excessive steam from machine

The steam valve seals by way of a hard teflon gasket, and over the years this seal can develop a groove and needs adjusting in order to get it to seal again. Remove the top of the machine and locate the steam valve on the front left side. With the steam valve fully closed, loosen the small hex bolt that holds the black steam valve stop in place and attempt to close the steam valve further. Then re-tighten the hex bolt, fire the machine up and see if it still leaks. If so, you may need to remove the knob/valve assembly and either flip over or replace the teflon seal.