Detailed explanation of automobile refrigerant filling


Why do we need to add refrigerant? Refrigerant is the w […]

Why do we need to add refrigerant?

Refrigerant is the working medium in the refrigerator, called refrigerant or refrigerating working medium. It circulates in the refrigeration system, and the refrigeration unit exchanges energy with the outside through the change of its thermal state in the refrigeration system, so as to realize the control Take the cold amount of the day. If there is no refrigerant, the air conditioner will not have air-conditioning. Most modern ones use R134a refrigerant.

The refrigerant

When should I add refrigerant?

1. Air conditioners that have been continuously used for more than 3 years and have not been added with refrigerant should be pressure tested on the machine's refrigerant, and adequate refrigerant should be properly supplemented;

2. When the cooling effect of the air conditioner is relatively poor, and the cooling speed becomes slow, you should consider whether the refrigerant is insufficient;

3. When the air conditioner cannot be cooled at all, and the compressor is working normally, it should be tested whether the air conditioner refrigerant is leaking, and the solution should be leak detection, leak repair, vacuuming, and adding refrigerant;

4. When the refrigeration system is dirty and blocked, the pipes will be blocked and the cooling effect will be poor or the phenomenon of no cooling;

5. When the air conditioner has been disassembled or replaced with copper pipes, the refrigerant should be refilled in time.

How to add refrigerant?

Get to know the tools before filling

Refrigerant filling tool

Manifold pressure gauge group is composed of high pressure gauge, low pressure gauge, high pressure manual valve, low pressure manual valve and three hose joints. The manifold pressure gauge group is equipped with three connecting hoses of different colors. Generally, it is stipulated that the blue hose is used for the low pressure side, the red hose is used for the high pressure side, and the yellow hose is used for the middle, which is connected to the vacuum pump or the refrigerant tank.

Connecting adapters and precautions

When the pressure joint is connected with the hose, it can only be tightened by hand, and no tools can be used.

When using, try to exhaust the air inside.

When not in use, plugs should be used to seal each interface to prevent moisture or debris from entering the pipe.

This meter is a precision instrument, it should be kept clean at ordinary times, and it should be handled with care when using it.


After the automobile air-conditioning refrigeration system is repaired, because it is exposed to air, a vacuum pump must be used to remove the moisture and air in the refrigeration system to maintain the normal operation of the air-conditioning refrigeration system. Vacuuming does not directly pump the moisture out of the refrigeration system, but produces After vacuum, the boiling point of the refrigerant is lowered, and the water is pumped out of the refrigeration system in the form of vapor. Before vacuuming, a refrigerant leak check should be carried out. Vacuuming is also to further check the airtight performance of the system under vacuum.


Refill refrigerant

One is to inject liquid refrigerant from the high-pressure side, which is charged by the pressure difference and position difference between the refrigerant tank and the system. This method is suitable for the situation where the system is evacuated without refrigerant. , It is characterized by fast speed; another method is to inject gaseous refrigerant from the low pressure side, which is suitable for replenishing a small amount of refrigerant into the system.

High pressure filling refrigerant

In addition, it should be noted that when charging refrigerant in this way, it is not allowed to open the low-pressure manual valve on the manifold pressure gauge, and it is never allowed to run the compressor, otherwise the refrigerant tank may burst.

Low pressure filling

Connect the manifold pressure gauge to the overhaul valve of the refrigeration system

Start the engine and keep it running at a speed of l500~2000r/min, turn on the air conditioner A/C switch to make the compressor work

Open the refrigerant tank with the injection valve and keep the tank upright, slowly open the low pressure manual valve of the manifold pressure gauge.

If you are using a small-capacity tank, you can close the low-pressure side manual valve on the manifold pressure gauge, remove the injection valve from the empty tank, and install it in the refrigeration tank to be used when the tank still needs to be filled after filling one tank. On the agent tank, exhaust the air in the middle injection hose, and then continue to fill it up to the right amount.

After filling, close the manual valve on the low pressure side of the manifold pressure gauge.

Precautions for filling refrigerant

Low-pressure side filling cannot be inverted

Do not open the high-pressure valve when filling on the low-pressure side

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