Why does the low-pressure pipe of the car air conditioner freeze? How to troubleshoot the freezing of the car air conditioner

Air conditioning is also one of the systems of the car. There are two types: heating and cooling. Air conditioning uses liquid refrigerant for cooling. After gasification, it turns into water vapor when it encounters heat and absorbs heat. Car air conditioning has high-pressure pipes and low-pressure pipes. Sometimes the low-pressure pipe freezes. What is the problem?

Why does the low-pressure pipe of the car air conditioner freeze?

The low-pressure pipe of the car air conditioner is frozen, and there may be different fault points for different models. Common reasons include abnormal operation of the expansion valve or evaporator temperature sensor, excessive refrigerant filling, leakage of the evaporator core of some models, insufficient refrigerant, etc., which may cause the low-pressure pipe of the air conditioner to freeze. If the air conditioner is frozen and no air is blown out of the air outlet, you can first connect a pressure gauge to check the refrigerant pressure. If too much refrigerant is added during maintenance, it can be improved by reducing the excess refrigerant to the normal range. If there is no problem with the refrigerant pressure, you need to eliminate the working conditions of the air conditioner temperature control sensor and the expansion valve.

In addition to the above routine inspections, if it is a variable frequency air conditioner, it is best to combine the diagnostic computer and read the data stream of the relevant sensors of the air conditioning control system to better analyze the cause of the air conditioning freezing.

How to troubleshoot car air conditioning icing

1. Check whether the evaporator temperature sensor is normal.

If the compressor stops rotating after freezing and no air is produced, then the temperature sensor fault can be ruled out.

Second, the expansion valve is faulty.

If the expansion valve is opened too wide, the evaporator temperature will be too low, causing ice blockage. Replacing the expansion valve can solve this problem.

3. Have you added refrigerant recently?

It is best not to add refrigerant to different products. In addition, poor quality refrigerant contains moisture, which can easily cause ice blockage. This requires vacuuming and replacing the refrigerant to solve this problem.

The general solution to this problem is to replace the expansion valve, then pressurize it, then vacuum it, and then replace the refrigerant.

Does the car air conditioning pump need to change the refrigeration oil?

If the air conditioner compressor is not stuck, it is generally not necessary to clean the air conditioner pipes or replace the refrigerant oil; the air conditioner pump is also called a compressor, and the lubricant in the compressor circulates throughout the system together with the refrigerant. After replacing any parts or a large amount of refrigerant leaks, it is necessary to add lubricant, that is, refrigerant oil, to the compressor.