The Johnson Controls® S-224 Pneumatic  Gradual Switch provides manual selection of  the pressure in air lines from a remote  location. The S-224 is a proportional action  relay type switch that maintains a selected  output pressure setting until it is readjusted. The setting can range from 0 to full supply  pressure up to 20 psig. The extremely stable  output of the S-224 makes the switch ideally  suited for position controlled devices or for  use as a remote pneumatic set point adjuster. A model is available with 2 psi span per dial  revolution of 300 angular degrees. Graduated  dials are available with various inscriptions to  adapt the switches to a broad range of  functions. The 2 psi span switch can be used  with 0 to 20 or 6 to 12 psi span dials. Refer to S-224 Pneumatic Gradual Switch  Product Bulletin (LIT-7171370P) and S-224  Gradual Switch Dials Construction Bulletin  (LIT-7171370X) for important product  information.