Pneumatic thermostats and retrofit kits regulate the heating or cooling within a space using air pressure. These thermostats are commonly used in older buildings with existing pneumatic systems, such as schools, hospitals, and commercial properties. Pneumatic thermostats respond to changes in temperature by increasing or decreasing the air pressure in a series of air-filled tubes. The change in pressure signals controllers or powers devices like dampers or valve actuators directly. Pneumatic thermostat retrofit kits convert existing pneumatic thermostats to a newer or competitive model when they become obsolete or unavailable. Direct-digital-control (DDC) pneumatic thermostats provide remote temperature monitoring and control using an existing pneumatic system. Pneumatic thermostat accessories repair, replace, or enhance pneumatic thermostats.