De Dietrich 95363311 Sicherheitsthermostat 110C

The De Dietrich 95363311 is a mechanical safety thermostat with a fixed switching point of 110°C. Parts of this type serve as a temperature limit device within the boiler, typically mounted on the flow pipe or heat exchanger. When the water temperature reaches the set point, the thermostat opens or closes its contacts, interrupting the burner control circuit or triggering a safety shutdown. Unlike NTC sensors, which provide a variable resistance signal to the control board, a safety thermostat acts directly and independently, making it a critical component for over-temperature protection. Selection for such a thermostat depends on the switching temperature, the reset type (automatic or manual), and the mechanical form (immersion stem, capillary bulb, or surface-mount). For a part of this type, the reset behaviour determines whether the boiler restarts automatically after the temperature drops or requires manual intervention. The switching point must match the boiler’s safety limit; a 110°C rating indicates a high-limit application, often found on oil or gas boilers where water temperatures can exceed normal operating ranges. When replacing a safety thermostat of this class, ensure the physical mounting fits the existing pocket or bracket, and verify the electrical ratings (voltage and current) are compatible with the burner control. Common failure modes include contact welding (loss of switching function) or drifting of the switching point due to thermal fatigue. A genuine De Dietrich part is recommended for proper form and calibration, especially where the thermostat is matched to a specific boiler series.