中文
含义
F22 表示干衣机的热敏电阻（进风口温度传感器）信号异常。肯摩尔干衣机在进风道内装有一个负温度系数（NTC）热敏电阻，用于实时监测进入滚筒的热空气温度。主控板通过读取热敏电阻的阻值变化来计算当前进气温度，并据此调节加热元件的通断周期，以确保烘干温度在设定的安全范围内。当热敏电阻信号超出合理范围（通常为短路对应极低阻值、断路对应极高阻值，或读数与环境温度严重不符），主控板判定传感器回路故障并显示 F22 代码。此状态下加热功能将被禁用，机器可能只翻滚不出热风。
常见原因
- 热敏电阻探头表面积聚棉絮、灰尘或纤维，形成隔热层，导致传感器响应滞后且读数偏低。
- 热敏电阻本身老化或内部半导体材料退化，阻值-温度曲线偏移，在正常温度下输出错误的阻值。
- 热敏电阻连接线束在长期高温环境下绝缘层脆化开裂，内部导线折断或与邻近线路短接。
- 热敏电阻插接端子因振动松脱或接触点氧化，导致信号时断时续，主控板检测到开路。
- 进气风道堵塞严重，热敏电阻局部温度异常升高，反复过热导致传感器永久性损坏。
- 主控板上对应热敏电阻输入通道的 ADC 采样电路故障（如分压电阻变值或输入滤波电容漏电），导致正确的传感器信号被误读。
- 滚筒前部或后部的密封圈破损漏气，热风短路回流到进风口，使热敏电阻所处的温度场混乱。
自助排查
- 断开干衣机电源，打开前下方检修面板（或根据机型打开后盖），找到位于进风道上的热敏电阻（通常为圆柱形探头，连接两根细线）。目视检查探头表面是否有明显棉絮包裹，用干燥软布或软毛刷轻轻清洁探头表面。
- 用万用表电阻档测量热敏电阻两端阻值。在室温（约 20–25 °C）下，NTC 热敏电阻典型阻值约为 10 kΩ–50 kΩ（具体参考维修手册）。若读数为零（短路）或无穷大（断路），说明热敏电阻已损坏，需更换。
- 用手指捏住热敏电阻探头加热约半分钟后再次测量，阻值应有明显下降（NTC 特性，温度升高→阻值减小）。若阻值完全不变，说明传感器失效。
- 沿热敏电阻线束追溯到主控板，检查整条线束有无被滚筒摩擦、金属边缘剪切或高温烤焦的痕迹，发现破损应用耐高温胶带包裹或更换线束。
- 重新插紧热敏电阻的插接端子，确保听到”咔嗒”锁紧声。如有条件，用电子清洁剂喷洗端子以去除氧化。
- 检查进风口滤网和风道有无棉絮堵塞，清洁整个进风路径。棉絮积聚不仅影响温度检测准确性，也是烘干效率低下的主要原因。
- 若传感器和线束均正常但仍报 F22，则故障可能位于主控板的 ADC 采样通道。此情况需专业人员使用示波器进一步诊断，请联系肯摩尔售后检修或更换主控板。
English
Meaning
F22 indicates an abnormal signal from the dryer’s thermistor (intake air temperature sensor). Kenmore dryers have a negative temperature coefficient (NTC) thermistor installed in the intake air duct to monitor the temperature of heated air entering the drum in real time. The main control board reads the thermistor’s changing resistance to calculate the current intake air temperature and adjusts the heating element’s on-off duty cycle accordingly, keeping the drying temperature within a safe set range. When the thermistor signal falls outside the acceptable range (typically a short circuit producing extremely low resistance, an open circuit producing extremely high resistance, or readings significantly inconsistent with ambient temperature), the control board flags a sensor loop fault and displays the F22 code. In this state, the heating function is disabled, and the machine may tumble without producing hot air.
Common Causes
- Lint, dust, or fiber buildup on the thermistor probe surface, forming an insulating layer that causes delayed sensor response and low temperature readings.
- The thermistor itself has aged or its internal semiconductor material has degraded, shifting the resistance-temperature curve and outputting incorrect resistance values at normal temperatures.
- The thermistor wiring harness insulation has become brittle and cracked from prolonged exposure to high temperatures, with internal conductors broken or shorted to adjacent wiring.
- The thermistor connector plug has loosened due to vibration or the contact points have oxidized, causing intermittent signal loss and the control board detecting an open circuit.
- The intake air duct is severely clogged, causing abnormally high localized temperatures at the thermistor; repeated overheating has permanently damaged the sensor.
- The ADC sampling circuit on the main control board for the thermistor input channel has failed (e.g., voltage-divider resistor drift or input filter capacitor leakage), causing correct sensor signals to be misread.
- The front or rear drum seal is torn and leaking air, allowing hot air to short-circuit back to the intake, disrupting the temperature field around the thermistor.
Self-Check Steps
- Disconnect the dryer from power. Open the lower front access panel (or rear panel depending on model) and locate the thermistor in the intake air duct (typically a cylindrical probe with two thin wires connected). Visually inspect the probe surface for lint buildup and gently clean it with a dry, soft cloth or soft brush.
- Using a multimeter in resistance mode, measure the thermistor’s resistance across its two terminals. At room temperature (approximately 20–25 °C / 68–77 °F), an NTC thermistor typically reads around 10 kΩ–50 kΩ (refer to the service manual for exact specifications). A reading of zero (short circuit) or infinite (open circuit) indicates the thermistor is damaged and must be replaced.
- Pinch the thermistor probe between your fingers to warm it for about 30 seconds and measure again — the resistance should drop noticeably (NTC characteristic: higher temperature → lower resistance). If the reading does not change at all, the sensor has failed.
- Trace the thermistor wiring harness all the way back to the main control board. Inspect the entire harness for signs of rubbing by the drum, cutting by metal edges, or scorching from high heat. Wrap any damaged sections with high-temperature tape or replace the harness.
- Reseat the thermistor connector plug firmly until you hear a click for the locking tab. If available, spray the terminals with electronic contact cleaner to remove oxidation.
- Check the intake air filter and duct for lint blockages and clean the entire intake air path. Lint accumulation not only affects temperature detection accuracy but is also the primary cause of reduced drying efficiency.
- If the sensor and harness both check out but the F22 code persists, the fault likely lies in the ADC sampling channel on the main control board. This requires an oscilloscope for further diagnosis by a professional. Contact Kenmore after-sales service for inspection or control board replacement.