中文
含义
四通换向阀故障。四通阀是热泵型空调制冷/制热切换的关键部件，故障导致模式切换异常、制冷制热效果差或完全不换向。
常见原因
- 四通阀线圈烧毁或开路，电磁力不足以驱动阀芯
- 四通阀芯卡死（常见于长期未换向运行后首次切换）
- 四通阀滑块磨损或密封不严导致串气
- 四通阀驱动继电器触点损坏
- 系统压差不足导致阀芯无法正常换向
自助排查
- 切换制冷/制热模式，听室外机有无”咔哒”换向声
- 四通阀线圈两端有无220V/12V驱动电压（依系统设计）
- 如线圈有电压但不换向，可轻敲阀体辅助换向
- 四通阀损坏需更换阀门，需回收制冷剂后焊接更换
English
Meaning
Four-way reversing valve failure. The four-way valve is the key component for switching between cooling and heating modes in heat-pump ACs. Failure causes mode-switching problems, poor heating/cooling performance, or complete inability to reverse the cycle.
Common Causes
- Burned-out or open four-way valve coil, insufficient electromagnetic force to shift the spool
- Stuck valve spool, especially after long periods without mode switching
- Worn valve slide or poor sealing causing gas bypass between ports
- Damaged four-way valve relay contacts on the control board
- Insufficient system pressure differential to overcome spool friction
Self-Check Steps
- Toggle between cooling and heating modes and listen for a distinct “click” from the outdoor unit
- Measure the voltage across the four-way valve coil — typically 220V AC or 12V DC depending on design
- If the coil has power but the valve does not shift, a gentle tap on the valve body may help free the spool
- A defective four-way valve requires refrigerant recovery, brazing replacement, and system recharge by a professional