Honeywell Temperature sensor T7335D1008B

This NTC temperature sensor is used in Ferroli boilers, including the Arena C, Arena F, Diva C, Diva F, and DIVAtech models. It replaces OEM part numbers 39810230 and 36200640. The sensor provides a variable resistance signal to the control board to report temperatures in the heating system.

Parts of this type are selected by their resistance characteristic at a reference temperature (commonly 10 kΩ or 12 kΩ at 25 °C), probe form (immersion, clamp-on, or sleeve), cable length, and connector type. The actual values must be confirmed from the appliance documentation or the existing sensor. An incorrect characteristic or mechanical fit will cause the control board to read the wrong temperature.

Typical failure modes for NTC sensors include a drifting characteristic that causes incorrect modulation, a broken cable, or poor thermal contact between a clamp-on probe and the pipe. When a sensor fails, the equipment may modulate incorrectly or go into a safety lockout. Check the sensor’s resistance against the expected curve and inspect the cable and mounting.