sounds like you have a blockage in the pressure system,its a small bottle like object with a thin hose running up to the pressure switch,all you have to do is clean it out,its held on with three screws,before you work on the machine,remove the plug from the socket,dont just turn the switch off,if you take the top off,you will see the hose ,look for it near the top right hand side of the machine,it will run down to the pressure chamber,
gts
September 2010