Master 4510.443 thermal cut-out 110c with reset

The Master 4510.443 is a thermal cut‑out with manual reset, rated to open at 110 °C. It is listed under air heaters components. Parts of this type function as an over‑temperature safety device. They are installed in the air stream or near the heat exchanger of a forced‑air heater. When the air temperature reaches the set point, the internal bimetal disc trips and breaks the electrical circuit supplying the burner control or the fan. The manual reset button must be pressed after the appliance has cooled and the cause of the over‑temperature has been identified and corrected. This prevents automatic restart into a still‑dangerous condition. Selection of a replacement thermal cut‑out is based on the opening temperature (110 °C), the reset type (manual only), and the electrical rating of the contacts. The physical mounting arrangement – typically a bracket or clip that positions the sensing face in the airflow – should match the original part. The electrical connections (number and type of terminals) must also be compatible with the existing wiring. When replacing, verify that the new unit is mounted in the same orientation and location as the original; an incorrect position can delay or prevent proper sensing of the air temperature. Always disconnect the appliance from the mains supply before replacing any safety component. After installation, test the reset button for free movement, then carry out a functional check by simulating an over‑temperature condition according to the heater manufacturer’s instructions.