Pneumatic controls regulate compressed air signals to operate various HVAC system components. Pneumatic receiver-controllers respond to changes in pneumatic signals to control HVAC components. Variable air volume reset controllers regulate the variable air volume box to achieve optimal system efficiency. Pneumatic variable air volume kits retrofit compatible variable air volume boxes. Air-switching valves redirect an input air signal between multiple possible outputs. Electric-to-pneumatic transducers convert electrical signals into proportional air signals. Pneumatic relays respond to air signal changes by preventing or allowing airflow. Pneumatic positioning switches control air signals by adjusting their strength. Pneumatic gradual switches regulate system pressures on the connected line. Pneumatic-electric switches make or break electric connections in response to pressure changes. Pneumatic temperature dials convert pneumatic temperature signals to visible readings.