De Dietrich 95363357 limit thermostat 65C

This limit thermostat, catalogue articles 336.805.005 and manufacturer code 95363357, is a mechanical safety device that interrupts an electrical circuit when the sensed temperature reaches a fixed switching point. In a boiler or burner system, limit thermostats are installed in the flow pipe, on the heat exchanger, or inside the boiler jacket to prevent overheating. When the temperature exceeds the set value, the thermostat opens its contacts, which directly cuts power to the burner or signals the safety chain, causing a lockout. Such thermostats work independently of the electronic control board; they are a simple, reliable over-temperature protection. Parts of this type are selected primarily by their switching temperature – here 65 °C – and by the reset behaviour. Some limit thermostats reset automatically once the temperature drops below a certain differential; others require a manual reset button. The physical connection matters: a capillary bulb with a threaded immersion pocket, a clamp‑on sensor, or a bi‑metallic disc inside a housing. Also verify the electrical rating (voltage, current) and the number of switching contacts (normally closed, normally open, or changeover). The catalogue category “Thermostats” groups these parts; do not confuse a limit thermostat with an NTC sensor, which sends a variable resistance reading to the control board rather than acting as a switch. When replacing a limit thermostat, confirm that the switching temperature and reset type match the original part’s function. Check the mounting position – a capillary sensor must be inserted fully into its pocket, and a clamp‑on probe must have good thermal contact with the pipe surface. If the new thermostat has a manual reset, ensure the installer and end‑user know how to reset it correctly after a trip. A faulty limit thermostat may cause nuisance lockouts or fail to protect against overheating; always replace with a part that meets the original specifications.