Summary of Auto AC Maintenance and Common Faults and Case Analysis of Automobile Air Conditioning 21

The temperature at the air outlet of the air-conditioning compressor of the automobile is too high after running for ten minutes, and the air-conditioning is insufficient. The reason for the fault is that the expansion valve is opened too much, which makes the refrigerant in the evaporator too much, so that the excess liquid returns with the evaporated gas. In the compressor, hydraulic shock occurs in the compressor, resulting in poor cooling effect. Treatment method: remove the expansion valve, and turn the flow adjustment screw clockwise for 1 to 2 turns

The compressor of the car air conditioner feels cool, but the cooling effect is poor, and the high and low pressure gauges indicate high. The fault is that there is air in the refrigeration system, excessive refrigerant, and the condenser is too dirty, all of which make the cooling effect poor.

Treatment method: Release excess refrigerant from the low-pressure liquid valve until bubbles appear in the glass cover hole on the liquid storage tank. If it still does not work, re-evacuate the system, add refrigerant, and clean the condenser fins

The air at the air outlet of the car air conditioner is not cold,

There are air bubbles in the glass cover hole of the liquid storage tank, and the reading of the high and low pressure gauge is close to

The reason for the failure is that the refrigerant circulation is not enough, the evaporation of the car ac evaporator is small, and the cooling effect is poor. Treatment method: Find the leaking part of the system, repair and vacuum, fill enough refrigerant, the car air conditioner does not cool, the exhaust temperature is high, the cylinder head is hot, and the reading of the high and low pressure gauge is close to the treatment method: stop using the air conditioner, remove the compressor, replace it Use a new valve plate and cylinder head, if it can't be repaired, only replace the compressor. The car air conditioner has sufficient refrigerant, the high and low pressure indications are normal, the air conditioner in the car is insufficient, and the cooling is extremely slow. Treatment method: check and replace the damaged belt. The pointers of the air-conditioning, high and low pressure gauges do not move. After investigation, the cause of the fault is that the refrigeration switch is in poor contact or the electromagnetic clutch coil is damaged, and the compressor cannot work. Solution: use a three-meter to check the air-conditioning switch, check the contacts, and lead directly from the battery to the clutch. If it still does not work, the clutch should be replaced.

The high and low pressure gauges indicate normal. The reason for the fault is that the opening of the cold temperature control switch is too small and the compressor cooling time is not enough. Solution: Check the cold temperature control switch, and open it to the coldest position. Insufficient cooling air flow in the car; improper adjustment of the temperature control valve, control device and ventilation switch are not closed Treatment methods: Check whether the fan, air distribution system and evaporator are blocked, check whether the valve response is sensitive; the control switch is adjusted to the correct position. The exhaust pressure of the compressor is too high. The reason for the fault is that the engine in the car is too hot and the refrigerant is too much; there is air in the system; the ac condenser is too dirty, and the evaporation pressure of the evaporator is too high. Refrigerant, discharge air, add a small amount of refrigerant to make the pressure gauge indicate normal: the exhaust pressure of the air conditioner compressor for cleaning the condenser is too low, and the fault is found to be insufficient refrigerant; the suction pressure of the compressor is too low; the reed control valve is damaged Treatment method: Observe the bubbles in the glass tube. After five minutes, if the bubbles are not obvious, check the leakage, add an appropriate amount of refrigerant, check the compressor, and replace the parts. The outlet of the evaporator is not fastened, which makes the temperature transfer invalid; the expansion valve is not adjusted properly, and the suction throttle valve is not adjusted properly. Treatment methods: fasten the temperature sensing package and replace the expansion valve; check the operating condition and repair the evaporator of the automobile air conditioner as necessary If the pressure is too low, the capillary of the expansion valve is damaged, and the filter screen is too dirty; the piping or hose of the system is blocked. Treatment method: replace the expansion valve, clean the filter screen; replace the piping and hoses; check the operation status of the suction throttle valve and make necessary repairs.

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Post time: May-03-2022