De Dietrich 100004781 NTC temperature sensor AD218

The De Dietrich 100004781 NTC temperature sensor AD218 is a spare part listed under the temperature NTC sensors category. This type of component plays a role in the control loop of a boiler or burner system: NTC sensors report temperatures—such as flow, return, cylinder, or outdoor temperature—to the control board, which then adjusts modulation, valve positions, or pump operation accordingly. The sensor itself is a negative temperature coefficient thermistor, meaning its electrical resistance decreases as temperature rises. Parts of this type are selected by their resistance characteristic (for example, a specific resistance at 25 °C), the probe form (immersion, clamp-on, or sleeve), cable length, and connector type. When replacing an NTC sensor, note that typical failures include a drifting characteristic that causes the boiler to modulate incorrectly, a broken cable, or poor contact between a clamp-on probe and the pipe. This article is identified by its catalogue article 336.220.009 and manufacturer codes 100004781 and 336.220.009.