How to check the high and low pressure meter when the car air conditioner compressor is not working

　　How to check the high and low pressure meter when the car air conditioner compressor is not working?

　　1. The indications of the high and low pressure gauges are too low. This may be an internal failure of the compressor, such as damaged valve plates and valve plate gaskets. The compressor needs to be replaced from time to time. (The internal failure of the compressor will not cause the low pressure gauge. Indication is too low).

　　2. The indications of the high and low pressure gauges are lower than the normal value at the same time. This may be mainly because the refrigerant is insufficient. When we check, we will find that the high pressure tube generates slight heat and the low pressure tube appears slightly cold, but the temperature difference It’s not that big. It can be observed from the sight glass that bubbles appear every 1 to 2 seconds. At this time, check for leaks first, and then replenish the refrigerant after repairing the leaks.

　　3. When the low pressure meter is much lower than the normal value, at this time, there is no temperature difference between the high and low pressure pipes, and the air-conditioning is not cold, indicating that the refrigerant is seriously leaking.

　　4. The indication of the low pressure meter is close to zero, and the indication of the high pressure meter is much lower than the normal value. At this time, the air conditioning system usually shows that the air is not cold, and the pipeline before and after the expansion valve is frosted. The reason is that on the one hand It may be that the expansion valve is frosted and blocked, making the refrigerant unable to circulate in the system. At this time, the vacuum should be repeated and the refrigerant should be added again. On the other hand, the expansion valve temperature sensor may be damaged, causing the expansion valve If it is not turned on, check the bulb at this time.