De Dietrich 82187720 room temperature sensor

This is a De Dietrich 82187720 room temperature sensor, also listed under catalogue article 336.220.010. It belongs to the category of temperature NTC sensors. The product data gives the name, brand, and codes; no further specifications about its resistance, cable length, or connector type are supplied in the input. Parts of this type measure the ambient air temperature in the heated space and send the signal to the boiler control board. The control board uses that input to modulate the burner output and maintain the set room temperature. NTC sensors are passive components whose resistance decreases as temperature rises. They are selected primarily by their resistance characteristic (for instance 10 kΩ or 12 kΩ at 25 °C), the form of the sensing element (immersion, clamp-on, or a room sensor housing), the cable length and connector type, and the required tolerance. When replacing a room temperature sensor, the most critical parameter is the resistance curve: a mismatch will cause the boiler to modulate incorrectly. Other common failure modes include a drifting characteristic that gives false readings, a broken cable, or poor contact at the connector terminals. Always compare the original sensor's markings or measure its resistance at a known temperature before ordering a replacement.