pressure switch possibly faulty, or the pressure chamber blocked ,remove the lid locate the pressure switch which is roundish with a plastic pipe and wires on remove the pipe off the pressure switch blow down the pipe into the chamber if you go red pipe is blocked, if no joy remove pipe at the other end poke the hole clear with a stiff piece of wire IF YOU BLOW TOWARDS THE SWITCH END YOU SHOULD HEAR THE SWITCH CLICK replace both ends of pipe and now see if machine OVERFILLS.
wirecutterman, February 2009
