How do I change the function of the Von Duprin 7500 mortise lock from Lever ( classroom ) to NL ( night latch )?

To convert the Von Duprin 9975NL(Night Latch or Storeroom) to 9975L (Classroom) exit function follow these steps (Note: the mortise lock is shipped as Night Latch from the factory):

1. Turn the NL screw on 7500 mortise lock all the way in clockwise until screw is no longer visible. 
2. Will also need to make sure you are using a Classroom Function trim such as a Knob, Thumbpiece or Lever trim.

To convert the Von Duprin 9975L to 9975NL exit function follow these steps (Note: the mortise lock is shipped as Night Latch from the factory):

1. Turn the NL screw on 7500 mortise lock counter clockwise until flush with cover plate. 
2. Will also need to make sure you are using a Night Latch trim.