At completion of Stage 3, the left solenoid valve is de-energized. Air pressure on the outside of the left diaphragm increases as air flows through the tiny bleed hole in
the diaphragm. The air pressure on the outside of the diaphragm quickly equalizes with the internal air pressure of the dryer allowing the small spring on the outside
of the diaphragm to press the diaphragm against its seat, keeping air from exiting the silencer.
Note: Any air flowing through the dryer, passes through both towers.