Thermostat, safety, thermistor

The safety thermostat is a temperature regulation device for water heaters that can be a bulb aquastat or a diving case aquastat (manual reset thermostat).
The NTC is a spare part for boilers that allows controlling the temperature flowing through the heating pipes or in the sanitary section. This replacement part is also known as the temperature probe (either heating temperature probe or sanitary temperature probe) or the NTC. The NTC is often a klixon, meaning a spare part with a base topped with two metal rods that touch at room temperature. If the temperature is too high, the two rods of the NTC expand and separate. The temperature probe for boilers sends information to the circuit board of the heating device to stop the boiler as long as the anomaly occurs.
The thermistor is also a temperature probe that serves to check if the heat from the boiler's heat source is not too high. This is why it is also called an overheating thermostat.