NBC Filter Differential Pressure Switch (fig. 1-40).
NBC Filter Differential Pressure Switch Location.
The NBC filter differential pressure switch mounts to the floor in
the left sponson area just inboard of the precooler air inlet duct.
The switch has an electrical connector with three pins and two
pneumatic ports, high-pressure and low-pressure.
port has a threaded boss connected to a line that connects to the
recirculation mixing duct to sense the pressure of the air in the
duct upstream of the NBC filters. The low-pressure port also has a
threaded boss and connects to a line that connects to the duct
downstream of the NBC filters (fig. 1-41).
The switch actuates if the pressure in the
upstream side of the filter exceeds the pressure in the
downstream side of the filter by 32 ƒ1.5 inches of water