What are the common faults of car air conditioners

Uncooled or insufficient air-conditioning in automobile air conditioners are common faults of air conditioners, which are more common in the airtightness of the refrigeration system because of the strong permeability of the refrigerant R134a used in cars. In summary, there are three main areas: mechanical failure of the air-conditioning system, electrical circuit failure of the air-conditioning system, and refrigerant and refrigerating oil failure. Now we, Suzhou Zhongcheng New Energy Technology Co., Ltd., will introduce and analyze the specific common faults.

1. The electrical circuit of the air conditioning system is faulty:

Pressure sensor, temperature sensor, thermostat, compressor electromagnetic clutch, high and low pressure protection switch, expansion valve temperature sensor, etc.

2. Mechanical failure of air conditioning system:

The mechanical failures of the air-conditioning system mainly include compressor failure, condenser and fan failure, blower failure, liquid storage dryer, expansion valve failure and evaporator failure. Judging whether it is a compressor failure depends on whether the transmission belt is aging, cracked, slack or too tight, which affects the power transmission. The internal parts are damaged or worn, which affects the compression performance and manifests as abnormal noise inside the compressor. The compressor cylinder gasket blow-by and the inlet and outlet valves are damaged, which affects the compression performance.

The failure of condenser and fan mainly depends on whether the heat sink is covered by oil and dust, which affects heat dissipation. Whether the fan is running well. The failure of the blower depends on whether the operation is normal, which may result in insufficient air flow. The receiver dryer contains a filter and desiccant. Whether the filter is clogged may affect the flow of the refrigerant; whether the desiccant is ineffective, affecting the water absorption capacity, and may cause ice blockage. The normal desiccant is blue, and the desiccant that is saturated with water is red. The failure of the expansion valve depends on the opening and closing of the expansion valve port to control the flow of liquid refrigerant into the evaporator, which plays a role in regulating the cooling capacity. If the valve port is always opened too large, the refrigerant inflow is large, and the evaporator surface is over-cooled and frosted, causing refrigeration to stop for a long time; if the valve port is always opened too small, the refrigerant inflow is small, resulting in insufficient refrigeration. The evaporator depends on whether the heat sink is covered by oil and dust, which affects heat exchange; whether it is deformed, etc.

3. Faults caused by refrigerant and refrigerating oil:

There are many reasons for failures caused by refrigerant and refrigerating oil, including insufficient refrigeration caused by too much refrigerant, insufficient refrigeration caused by too little refrigerant, excessive impurities in refrigerant and refrigerating machine oil, insufficient refrigeration caused by micro-blocking, and air-conditioning refrigeration The infiltration of water in the system causes insufficient refrigeration, the presence of air in the system causes insufficient refrigeration, and the inferior refrigeration oil causes insufficient refrigeration.

If there is too much refrigerant, heat dissipation is slow. If too much refrigeration 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 air bubble in the sight glass when the car air conditioner is running, and there is no air bubble even after the compressor stops, it must be too much refrigerant. If too much refrigerating machine oil is added, turbid bubbles can be seen in the sight glass during normal operation of the air-conditioning system. If it is true that there is too much refrigerant, you can slowly release some from the maintenance port on the low pressure side of the air conditioning system.

The reason for the lack of refrigerant is mostly due to a small amount of refrigerant leakage in the system. Inspection method: Insufficient refrigerant can also be observed in the sight glass above the drying tank. When the air conditioner is operating normally, if there are continuous and slow bubbles in the sight glass, the refrigerant is insufficient. If there is an obvious bubble turnover, it means that the refrigerant is seriously insufficient, and the refrigerant and the refrigerating machine oil contain too much impurities and micro-blocking, which causes insufficient cooling capacity. Usually called dirty blockage: the filter screen of the drier, the expansion valve, the condenser, the evaporator, the high and low pressure pipes, etc.

When the water-containing refrigerant passes through the orifice of the expansion valve, due to the drop in temperature, the water molecules freeze in the small holes, causing the refrigerant to circulate unsmoothly, increase the resistance, or not flow at all. This phenomenon is called ice blocking. Repair method: stop for a while, after the ice melts, the refrigeration system will appear normal again. This is an important way to confirm the presence or absence of water in the system.

It is difficult for air to be compressed into liquefied gas. Therefore, when air enters the refrigeration system, the compressor discharge pressure and discharge temperature will increase, resulting in a decrease in output refrigeration capacity. The airtightness of the refrigeration system is deteriorated, or the vacuum is incomplete during maintenance. Inferior refrigerating oil will deposit on the surface of the condenser and evaporator as the refrigerant circulates, which affects the excessive pressure of the heat exchange air-conditioning system. The air is mixed in the system: the refrigerant is discharged, the vacuum is drawn, and the refrigerant is too much: Discharge excess refrigerant, poor condenser cooling: the cooling fins are blocked or the heat dissipation is not good, the cooling conditions need to be improved, and the high-pressure pressure switch is not working properly.

If you want to know more information about common failures of automobile air conditioners, please contact our Suzhou Zhongcheng New Energy Technology Co., Ltd. We can confirm a more accurate situation for you and provide you with exclusive professional services.