Automotive air conditioning is not cooling or inadequate air-conditioner failure is a common, more common in the cooling system sealing problems, because the refrigerant R134a used in modern cars permeability sake. Summed up in three main areas: air-conditioning system of mechanical failure, the air conditioning system electrical circuit fault, refrigerant and refrigerant oil failure. According to special margin fan clutch for your car air conditioner fails to explain the reasons:
First, the air conditioning system of mechanical failure
Mechanical failure include air-conditioning system compressor failure, condenser and fan failure, blower failure, reservoir dryer, expansion valve and evaporator fault fault. Determine whether the compressor drive belt failure depends on whether the aging, cracked, loose or too tight, the impact of power transmission. Internal parts damaged or worn, the impact of the compression performance, the performance of the internal compressor abnormal noise. Channeling gas compressor cylinder head gasket, intake and exhaust valve damage, the impact of the compression performance.
Condensers and heat sink fan failure mainly to see whether it is covered by oil, dust, impact of heat. Fan is running well. Blower failure depends functioning properly, may lead to insufficient air flow. Reservoir containing the filter drier is to see and desiccant. Filter is clogged, it may affect the refrigerant flow; desiccant whether the failure, affecting water absorption capacity, may cause ice block. Normal desiccant is blue, the desiccant is saturated with water red. Look through the expansion valve failure of the expansion valve port to control the opening and closing of the refrigerant entering the evaporator the liquid flow, regulate the cooling capacity. If the valve is too large mouth always open, the refrigerant flows to the evaporator surface due to cold frost, causing the cooling time to stop; If the valve is always open mouth is too small, the refrigerant flows into a small volume, resulting in insufficient cooling. Evaporator fins depends on whether it is oil, dust cover, the impact of heat exchange; whether deformation.
Second, the air-conditioning system electrical circuit malfunction
Pressure sensors, temperature sensors, thermostat, compressor electromagnetic clutch, high and low pressure protection switch, expansion valve bulb and so on.
Third, the refrigerant and refrigerant oil caused by the failure
Failures caused by refrigerant and refrigerant oil, for many reasons, including lack of refrigerant caused by excessive cooling, refrigerant shortage caused by too little refrigerant, the refrigerant and refrigerant oil contains too many impurities, caused by lack of micro-blocking cooling capacity, air conditioning and refrigeration the system has insufficient cooling water caused by infiltration, the system has resulted in insufficient cooling air and low-grade oil caused by lack of refrigeration and refrigeration.
If too much refrigerant, heat dissipation slow. If added too much maintenance refrigeration oil, the refrigeration system will also decrease the amount of heat. Repair methods: observation from above a dry tank sight glass. If the air conditioning in the car running from the sight glass can not see a little bubble, no bubble after a compressor stall, it is certainly too much refrigerant. If excessive amount of oil added to the refrigeration, air-conditioning system during normal operation, from the sight glass opacities seen more bubbles. If indeed excessive cooling agent can be repaired at the mouth of the low pressure side of the air conditioning system and slowly release some can be.
Most of the causes is due to the shortage of refrigerant in the refrigerant system micro leaks. Inspection method: to be shortage of refrigerant liquid mirror as viewed from the top of the tank to the drying, when the air conditioner normal operation, if the sight glass with slow continuous bubble generation, the refrigerant shortage. If the apparent air bubbles appear flip, then a serious shortage of refrigerant
Refrigerant and the refrigerating machine oil containing much impurities, micro insufficient cooling capacity caused by blocking. Often called dirty block: dry filter strainer, expansion valves, condensers, evaporators, high and low pressure pipe.
When the refrigerant passes through the expansion valve aqueous orifice, the temperature drop phenomenon of frozen water molecules in the pore and cause the refrigerant flow is not smooth, the resistance increases, or not at all flow. This phenomenon is called ice block. Repair methods: Stop for a while, until the ice melted, the normal state of the refrigeration system will appear. This is to confirm the presence or absence of water systems in important ways.
Air compressed liquefied gas is difficult, and therefore causes the compressor discharge air into the exhaust gas temperature and increased pressure in the cooling system, causing the output of the cooling capacity decreases. Refrigeration system tightness worse, or maintenance vacuum is not complete. Poor refrigeration oil circulating with the refrigerant in the condenser and the evaporator will be deposited surface of air conditioning system pressure causes excessive heat exchange is mixed with the air in the system: release the refrigerant, vacuum, excessive refrigerant: release the excess refrigerant, condenser cooling bad: cooling fins clogged or bad, need to improve the cooling conditions, high pressure switch is bad work.
