The most common failure of the air conditioning valve expansion valve is the jam, and the congestion of the thermal expansion valve in the refrigeration system is often occurring, including the dirty plug and the "ice plug".
The main reason for the dirty plugging is that there are impurities in the system, such as slag, copper, iron, fiber, etc. The reason for the ice jam is that the system contains too much water (moisture).
The method of obstruction fault exclusion of car air conditioning valve
For the dirt, if it's not very serious, change a dry filter. If it is very serious, you will reclean the impurities in the system line, vacuum the vacuum, and re-fill the refrigerant. For the light ice jam, the hot towel is applied to the ice block, and if the ice congestion is serious, it has affected the normal operation of the system, and the drying device has been removed, and the water in the system line is reused, the vacuum is vacuum and the refrigerant is recharged.