1.Working Principle Internal NTC thermistor: resistance decreases as temperature rises. The main board identifies the coil temperature through resistance changes to execute protection and operation logic. 2. Standard Specifications Resistance at 25℃: 5kΩ / 10kΩ B-value: 3435K, 3950K Temperature tolerance: ±1℃ Operating temperature: -40℃ ~ 120℃ Fast thermal conduction copper casing for quick response 3. Structure Composition Sealed NTC thermistor core Thin copper tube sensing head Spring metal clip (for tight pipe fitting) High temperature resistant wire Customizable connector terminals 4. Main Functions Anti-freezing protection in cooling mode: Avoid evaporator icing Auto defrost trigger in heating mode for outdoor condenser High temperature overload protection for compressor Assist to judge refrigerant shortage failure 5. Common Fault Manifestations Indoor coil frosts heavily, air output weakens Outdoor unit accumulates thick frost without defrosting Air conditioner pops pipe temperature error code and stops working Compressor starts and stops frequently 6. Application Scenarios Split air conditioner, cabinet AC, inverter heat pump, dehumidifier, refrigeration unit