Johnson Controls T-4100-1 Pneumatic Room Thermostat DA, Non-Relay,Vertical

The Johnson Controls T-4100-1 Pneumatic Room Thermostat is a vertical-mounted device that is intended for use in single zone temperature control of spaces in heating and cooling systems. Unlike digital thermostats, it employs the use of compressed air pressure in the management of temperature. When the room temperature is above or below the set point, the T-4100-1 varies the pressure that is delivered to a pneumatic HVAC device such as a damper or valve. This produces a direct ratio, which helps to prevent putting pressure on the heating or cooling system.