Excessive refrigerant in the sky is generally caused by excessive refrigerant filling during maintenance, because in

The volume ratio of refrigerant in air conditioning system has certain requirements. If the proportion is too large, it will affect its heat dissipation, that is, the more heat dissipation, the greater the refrigeration capacity; On the contrary, if the heat dissipation is small, the cooling capacity will be small. Similarly, if too much cooling oil is added during maintenance, the heat dissipation of the refrigeration system will also decrease.

Maintenance method: observe from the liquid mirror above the drying tank. If there is no bubble in the mirror when the automobile air conditioner is running, and there is no bubble after the compressor stops running, there must be too much refrigerant. If the amount of pressurized cooling oil is too much, turbid bubbles will appear in the observation window when the air conditioning system works normally. Of course, if there is too much refrigerant, you can slowly release some from the maintenance port on the low pressure side of the air conditioning system.

2. Too little refrigerant will lead to insufficient refrigerant.

The lack of refrigerant is mostly due to the slight leakage of refrigerant in the system. If the refrigerant in the air conditioning system is insufficient, the refrigerant injected into the evaporator from the expansion valve must also be reduced, so when the refrigerant evaporates in the evaporator. The absorbed heat will also be reduced, and the refrigeration capacity will also be reduced.

Inspection method: insufficient refrigerant can also be observed from the observation window above the drying tank. When the air conditioner is in normal operation, if there are continuous slow bubbles in the observation window, it means that the refrigerant is insufficient. If there is obvious bubble turnover, it means that the refrigerant is seriously insufficient. If the refrigerant is insufficient, it should be added, but it should be noted that if it is added from the low pressure side, it is forbidden to pour the refrigerant bottle, and if it is added from the high pressure side, it is forbidden to start the engine.

3. There are too many impurities in refrigerant and refrigerating machine oil, which are slightly blocked, resulting in insufficient refrigeration capacity.

If there are too many internal organs of refrigerant and refrigerating machine oil in the whole air conditioning system, it will block the filter screen of the filter, resulting in a decrease in refrigeration capacity and an increase in resistance, and the refrigerant flowing to the expansion valve will also be relatively reduced, resulting in insufficient refrigeration capacity. Therefore, when maintaining air conditioners, it is very important to choose qualified refrigerants, especially those "three days" products.

4, air conditioning refrigeration system has water infiltration caused by insufficient refrigeration.

A component of the refrigeration system is the drying tank (bottle), whose main task is to absorb the moisture in the refrigerant and prevent the cooling capacity from decreasing due to too much moisture in the refrigerant. However, when the desiccant in the drying tank is saturated with moisture, water can no longer be filtered out. When the refrigerant passes through the orifice of the expansion valve, due to the decrease of its pressure and temperature, the moisture in the refrigerant will freeze in the orifice, resulting in poor refrigerant circulation, increased resistance or no flow at all.

Maintenance method: After stopping for a period of time, the refrigeration system will return to normal after the ice melts. This is an important way to confirm whether there is water in the system. In order to better detect the amount of water in the system, the desiccant used by some cars is blue when there is no water. Once there is too much water, the desiccant will turn red, which can be seen on the side liquid hole on the drying water tank of the car.

If there is too much water in the refrigerant, the desiccant or drying tank should be replaced. At the same time, the system should be vacuumized again and injected with new refrigerant again.

5. The air in the system is also one of the reasons leading to insufficient refrigeration.

Once the air enters the air conditioning system, the pressure in the refrigeration pipeline will be too high, and poor refrigerant circulation will also cause insufficient refrigeration. This failure is mainly caused by poor sealing performance of refrigeration system or incomplete vacuum pumping during maintenance.

6, compressor drive belt looseness inspection

The transmission belt of air-conditioning compressor is loose, and the compressor will slip when working, which will lead to the decrease of transmission efficiency, compressor speed and compressed refrigerant delivery, thus directly reducing the refrigeration capacity of air-conditioning system.

The inspection method of the drive belt is as follows: When the engine is stopped, move the belt in the middle of the drive belt by hand, preferably by 90. If the rotation angle is too large, the drive belt is loose and should be tightened. If it is not rotated by hand, it means that the transmission belt is too tight and should be loosened slightly. Of course, if the fastening is invalid or the drive belt is damaged due to cracks and aging, a new drive belt should be replaced.

7. The decrease of condenser cooling capacity will also lead to the decrease of air conditioning cooling capacity.

Because of the different working environment of the automobile, the surface of the condenser installed in front of the automobile engine will be covered with oil or sundries, which will reduce its heat dissipation ability. In addition, the failure of cooling fan, such as loose drive belt, low fan speed or too high fan speed, will lead to the decrease of heat dissipation capacity of condenser. Solution: Brush off the dirt on the surface of the condenser with a soft brush, and remove the fault of the electric fan in time.

8. Other reasons

For example, the low power supply and voltage will reduce the suction of the compressor electromechanical clutch, or there is oil pollution between the pressure plate and pulley of the electric clutch, which will lead to the phenomenon of "slipping" similar to the loosening of the drive belt. If the surface of evaporator is frosted, the speed of blower motor will decrease, which will also cause insufficient cooling capacity. Of course, if the compressor is worn or the valve is improperly closed, it will also cause insufficient cooling capacity of the air conditioner.