Brahma NTC temperature sensor 18200309

Brahma NTC temperature sensor 18200309, also listed as 246.220.101, is a temperature sensor with the model designation ST06, featuring a red G1/8 thread and a 13 mm hex (CH13). It is categorized under temperature NTC sensors and is used in boiler and burner systems to report fluid temperatures to the control board. Typical measurement points include the flow pipe, return pipe, cylinder, and outdoor air. The sensor operates passively, requiring no power supply, and is wired directly to the control board's NTC input.

Parts of this type are selected by matching the resistance characteristic at a reference temperature (commonly 10 kΩ or 12 kΩ at 25 °C), the probe form (immersion, clamp-on, or sleeve), cable length and connector type, and the specific connection to the control board. When replacing a sensor, match the resistance curve and the physical mounting arrangement to the original. Ensure the probe tip is fully inserted or securely clamped to the pipe for accurate readings.

Common failures include a drifting resistance curve that causes incorrect modulation, broken cables, or poor thermal contact between a clamp-on probe and the pipe surface. A failing sensor may lead to unstable water temperature, frequent cycling, or lockout conditions. Check the sensor's resistance at a known temperature and inspect the cable and mounting for damage or poor contact.