This Therm-O-Disc MicroTemp thermal cut-off is engineered to interrupt the electrical circuit if internal temperatures exceed the critical 144°C (291°F) threshold

providing reliable protective redundancy for the heat exchanger

heat-resistant termination on the wiring harness

Internal diagnostics typically show a "3-flash" or "flame loss" code

Johnson Controls T-4000-2142 Plastic Cover This Therm-O-Disc MicroTemp thermal cut-offThe Johnson Controls T 4000 2142 is a professional grade horizontal pneumatic thermostat cover designed specifically for the T 4000 series. This beige plastic thermostat cover facilitates precise environmental monitoring and adjustment in commercial HVAC pneumatic control systems. Engineered for horizontal mounting, it features an integrated Fahrenheit and Celsius thermometer and a single setpoint window to ensure clear visibility of system