Johnson Controls D 4073 1 Damper Actuator 30067439 890 verify your supply line and verify your supply line and burner tube diameter to ensure compatibility with these larger 3 4" ports compared to 1 2" variants Key Benefits Precise Thermal Calibration: Factory set L170 40F rating ensures the Reznor 57953 trips at exactly 170°F to protect the heat exchanger Durable Construction: The glass reinforced polymer body offers superior corrosion resistance compared to traditional metal actuators in demanding environments Maintenance is simplified by a two way swivel connection that prevents binding and a telescoping piston rod that allows for fast linkage adjustments